muscular system -...
TRANSCRIPT
Jhia Anjela D. Rivera
Department of Biological Sciences, School of Science and Technology, Centro Escolar University
MUSCULAR SYSTEM
OUTLINE
• Overview
• Major types of muscles
• Muscle nomenclature
• Attachments of skeletal muscles
• Muscle forms
• Regional study of skeletal muscles• Muscles of the thorax• Muscles of respiration• Muscles of the back• Muscles of the anterior abdomen• Muscles of the posterior abdomen• Muscles of the perineum• Muscles of the upper extremity• Muscles of the lower extremity
• Identify origin, insertion, action and nerve supply
• Clinical considerations
OBJECTIVES
• To describe the properties and functions of the different muscle tissues.
• To identify the contrast between skeletal, cardiac and smooth muscles.
• To know the different bases for naming muscles.
• To differentiate muscular attachments.
MUSCULAR SYSTEM
• Generally regarded as consisting of one type of muscle found in the body – skeletal muscle
FUNCTIONS OF THE MUSCULAR SYSTEM
Muscle tissue is highly specialized to contract, or shorten, forcefully. The process of metabolism extracts energy from nutrient molecules. Part of that energy is used for muscle contraction, and the remainder is used for other cell processes or is released as heat.
• Body movement
• Maintenance of posture
• Respiration
• Production of body heat
• Communication
• Constriction of organs and vessels
• Heart beat
PROPERTIES OF MUSCLES
Muscle has four major functional properties:
• Contractility is the ability of muscle to shorten forcefully
• Excitability is the capacity of muscle to respond to a stimulus
• Extensibility means that muscle can be stretched beyond its normal resting length and is still able to contract
• Elasticity is the ability of muscle to recoil to its original resting length after it has been stretched
TYPES OF MUSCLE TISSUES
• Forms the majority of the muscle tissue in the body
• Consists of parallel bundles of long, multinucleated fibers with transverse stripes
• Capable of powerful contractions, innervated by somatic and branchialmotor nerves
• Used to move bones and other structures, provides support and gives form to the body
Skeletal
• Striated muscle found only in the walls of the heart (myocardium) and in some of the large vessels close to where they join the heart
• Consists of a branching network of individual cells linked electrically and mechanically
• Less powerful contractions, resistant to fatigue
• Innervated by visceral motor nerves
Cardiac
• Absence of stripes
• Consists of elongated or spindle shaped fibers capable of slow and sustained contractions
• Found in the walls of blood vessels (tunica media), associated with hair follicles in the skin, in the eyeballs, GIT, urinary system
• Innervated by visceral motor nerves
Smooth
MUSCLE NOMENCLATURE
Muscles are named according to:
• Location
• Size
• Shape
• Orientation of fasciculi
• Origin and insertion
• Number of heads
• Function
LOCATION
• A pectoralis (chest) muscle is located in the chest, a gluteus (buttock) muscle is located in the buttock, and a brachial (arm) muscle is located in the arm.
SIZE
• The gluteus maximus (large) is the largest muscle of the buttock, and the gluteus minimus (small) is the smallest. A longus (long) muscle is longer than a brevis (short) muscle.
SHAPE
• The deltoid (triangular) muscle is triangular, a quadratus (quadrate) muscle is rectangular, and a teres (round) muscle is round.
ORIENTATION OF FASCICULI
• . A rectus (straight) muscle has muscle fasciculi running straight with the axis of the structure to which the muscle is associated, whereas the fasciculi of an oblique muscle lie oblique to the longitudinal axis of the structure.
ORIGIN AND INSERTION
• The sternocleidomastoid originates on the sternum and clavicle and inserts onto the mastoid process of the temporal bone. The brachioradialis originates in the arm (brachium) and inserts onto the radius.
NUMBER OF HEADS
• A biceps muscle has two heads, and a triceps muscle has three heads.
FUNCTION
An abductor moves a structure away from the midline, and an adductor moves a structure toward the midline. The masseter (a chewer) is a chewing muscle
ATTACHMENTS OF SKELETAL MUSCLES
• Tendon – muscle to bone
• Aponeuroses – muscle to muscle
• Origin (head) – stationary end of the muscle
• Insertion – end of the muscle attached to the bone
• Belly – part of the muscle between the origin and insertion
REGIONAL STUDY OF SKELETAL MUSCLES
• Thorax
• Respiration
• Back
• Anterior abdomen
• Posterior abdomen
• Perineum
• Upper extremity
• Lower extremity
MUSCLE OF THE THORAX AND RESPIRATION
MUSCLE ORIGIN INSERTION INNERVATION ACTIONExternal intercostal
(11 muscles)Lower border of a rib Upper border of the
rib belowIntercostal nerves Elevate the ribs;
active during normal inspiration
Within intercostal space, each extends fromthe tubercle of the rib dorsally to thecartilage of the rib ventrally
Internal intercostal(11 muscles)
Ridge on the inner surface near lower border of the rib
Upper border of the rib below
Intercostal nerves Elevate the ribs; active during
inspiration and expiration
Within intercostal space, each extends from the sternum ventrally to the angle of the rib dorsally
MUSCLE OF THE THORAX AND RESPIRATIONMUSCLE ORIGIN INSERTION INNERVATION ACTION
Transversus thoracis Inner surface of body; xiphoid process,posterior surface of the sternum
Costal cartilages of ribs 2-6,
inner surfaces of costal cartilages 2-6
Intercostal nerves compresses the thorax for forced
expiration
Subclavius 1st rib and its cartilageat their junction
Groove on the lower surface of the middle 1/3rd of clavicle
Nerve to subclavius from upper trunk of brachial plexus
Depresses and pulls clavicle forward
Subcostalis angle of ribs angle of a rib 2-3 ribs above origin
Intercostal nerves compresses the intercostal spaces
Diaphragm xiphoid process, costal margin, fascia over the quadratus lumborumand psoas major mm.(lateral & medial arcuate ligaments), vertebral bodies L1-L3
central tendon of the diaphragm
phrenic nerve (C3-C5) pushes the abdominal viscera
inferiorly, increasing the volume of the
thoracic cavity (inspiration)
MUSCLES OF THE THORAX AND RESPIRATION
MUSCLE OF THE BACK
MUSCLE ORIGIN INSERTION INNERVATION ACTIONErector spinae iliac crest, sacrum,
transverse and spinous processes of
vertebrae and supraspinal ligament
angles of the ribs, transverse and
spinous processes of vertebrae, posterior aspect of the skull
segmentally innervated by dorsal primary rami of spinal nerves C1-S5
extends and laterally bends the
trunk, neck and head
Iliocostalis iliac crest andsacrum
angles of the ribs dorsal primary rami of spinal nerves C4-S5
extends and laterally bends the
trunk and neck
Interspinales upper border of spinous process
lower border of spinous process
above
dorsal primary rami of spinal nerves C1-L5
extend trunk and neck
Intertransversarii upper border of transverse process
lower border of transverse process above
dorsal primary rami of spinal nerves C1-L5
laterally bend trunk and neck
MUSCLE OF THE BACK
MUSCLE ORIGIN INSERTION INNERVATION ACTIONLongissimus transverse process at
inferior vertebral levels
transverse process at superior vertebral levels and mastoid
process
dorsal primary rami of spinal nerves C1-S1
extends and laterally bends the
trunk, neck and head
Multifidus sacrum, transverseprocesses of C3-L5
spinous processes 2-4 vertebral levelssuperior to theirorigin
dorsal primary rami of spinal nerves C1-L5
extend and laterally bend
trunk and neck, rotate to opposite
side
Obliquus capitisinferior
spinous process of the axis
transverse process of atlas
suboccipital nerve (DPR of C1)
rotates the head to the same side
Obliquus capitissuperior
transverse process of atlas
occipital bone above inferior nuchal line
suboccipital nerve (DPR of C1)
extends the head, rotates the head to
the same side
MUSCLE OF THE BACKMUSCLE ORIGIN INSERTION INNERVATION ACTIONRectus capitis
posterior majorspinous process of
axisinferior nuchal line suboccipital nerve
(DPR of C1)extends the head,
rotate to same side
Rectus capitisposterior minor
posterior tubercle of atlas
inferior nuchal linemedially
suboccipital nerve (DPR of C1)
extends the head
Rotatores transverse processes long rotatores: spines 2 vertebrae above origin; short rotatores: spines 1 vertebrae above
origin
dorsal primary rami of spinal nerves C1-L5
rotates the vertebral column to the opposite
side
Semispinalis transverse processes of C7-T12
capitis: back of skull between nuchal lines; cervicis & thoracis: spines 4-6 vertebrae above origin
dorsal primary rami of spinal nerves C1-T12
extends the trunk and laterally bends the trunk, rotates the trunk to the
opposite side
MUSCLE OF THE BACKMUSCLE ORIGIN INSERTION INNERVATION ACTION
Spinalis spinous processes at inferior vertebral levels
spinous processes at superior vertebral
levels and base of the skull
dorsal primary rami of spinal nerves C2-L3
extends and laterally bends trunk and
neck
Splenius ligamentum nuchaeand spines C7-T6
capitis: mastoidprocess & superiornuchal line laterally;cervicis: posteriortubercles of C1-C3vertebrae
dorsal primary rami of spinal nerves C2-C6
extends and laterally bends neck and
head; rotates head to same side
Splenius capitis ligamentum nuchaeand spines of C7-T6
vertebrae
mastoid process and lateral end of the
superior nuchal line
dorsal primary rami of spinal nerves C2-C6
extends and laterally bends the neck and
head, rotates head to the same side
Splenius cervicis ligamentum nuchaeand spines of C7-T6 vertebrae
posterior tubercles of the transverse processes of C1-C3 vertebrae
dorsal primary rami of spinal nerves C2-C6
extends and laterally bends neck and
head, rotates head to the same side
MUSCLE OF THE BACK
MUSCLE OF THE BACK
MUSCLE OF THE BACK
MUSCLE OF THE BACK
MUSCLE OF THE ABDOMENMUSCLE ORIGIN INSERTION INNERVATION ACTION
Cremaster inguinal ligament forms thin network of muscle fascicles around the spermatic cord and
testis (or around the distal portion of the
round ligament of the uterus)
genital branch of the genitofemoral nerve
elevates testis (not well developed in
females)
Dartos subcutaneous connective tissue of the scrotum and the penis (or labium majus and
clitoris)
skin of the scrotum andpenis (or labium majusand clitoris)
postganglionic sympathetic nerve fibers arriving via the ilioinguinal nerve and the
posterior scrotal nerve
elevates testis (tenses the skin of the
pudendal region in the female)
External abdominal oblique
lower 8 ribs linea alba, pubic crest & tubercle, anterior
superior iliac spine & anterior half of iliac crest
intercostal nerves 7-11, subcostal, iliohypogastric
and ilioinguinal nerves
flexes and laterally bends the trunk
Interfoveolar transversus abdominisfibers that lie superficial to the inferior epigastricvessels
anterior lamina of femoral sheath, immediately distal to origin of inferior epigastric vessels
iliohypogastric and ilioinguinal nerves
compresses abdominal contents
MUSCLE OF THE ABDOMENMUSCLE ORIGIN INSERTION INNERVATION ACTION
Internal abdominal oblique
thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the
inguinal ligament
lower 3 or 4 ribs, lineaalba, pubic crest
intercostal nerves 7-11, subcostal, iliohypogastric
and ilioinguinal nerves
flexes and laterally bends the trunk
Oblique, external abdominal
lower 8 ribs linea alba, pubic crest& tubercle, anteriorsuperior iliac spine &anterior half of iliaccrest
intercostal nerves 7-11, subcostal, iliohypogastric
and ilioinguinal nerves
flexes and laterally bends the trunk
Oblique, internal abdominal
thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the
inguinal ligament
lower 3 or 4 ribs, lineaalba, pubic crest
intercostal nerves 7-11, subcostal, iliohypogastric
and ilioinguinal nerves
flexes and laterally bends the trunk
Psoas major bodies and transverse processes of lumbar vertebrae
lesser trochanter of femur (with iliacus) via iliopsoas tendon
branches of the ventral primary rami of spinal
nerves L2-L4
flexes the thigh; flexes & laterally
bends the lumbar vertebral column
MUSCLE OF THE ABDOMENMUSCLE ORIGIN INSERTION INNERVATION ACTION
Psoas minor bodies of the T12 & L1 vertebrae
iliopubic eminence at the line of junction of
the ilium and the superior pubic ramus
branches of the ventral primary rams of spinal
nerves L1-L2
flexes & laterally bends the lumbar vertebral column
Pyramidalis pubis, anterior to the rectus abdominis
linea alba subcostal nerve draws the linea alba inferiorly
Quadratus lumborum posterior part of the iliac crest and the
iliolumbar ligament
transverse processes of lumbar vertebrae 1-4
and the 12th rib
subcostal nerve and ventral primary rami of
spinal nerves L1-L4
laterally bends the trunk, fixes the 12th
rib
Rectus abdominis pubis and the pubic symphysis
xiphoid process of the sternum and costal cartilages 5-7
intercostal nerves 7-11 and subcostal nerve
flexes the trunk
Transversus abdominis lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament
linea alba, pubic crest and pecten of the pubis
intercostal nerves 7-11, subcostal, iliohypogastric
and ilioinguinal nerves
compresses the abdomen
MUSCLE OF THE ANTERIOR ABDOMEN
MUSCLE OF THE ANTERIOR ABDOMEN
MUSCLE OF THE ANTERIOR ABDOMEN
MUSCLE OF THE ANTERIOR ABDOMEN
MUSCLE OF THE ANTERIOR ABDOMEN
MUSCLE OF THE ANTERIOR ABDOMEN
NEXT MEETING
• Muscles of Perineum
• Muscles of the upper and lower extremities
• Clinical Considerations
MUSCLES OF THE PELVIC WALLS
MUSCLE ORIGIN INSERTION INNERVATION ACTION
Obturator internus –flat, fan-shaped muscle
Anterolateral wall of true pelvis (deep
surface of obturatormembrane and
surrounding bone)
Medial surface of greater trochanter of
femur
Nerve to obturatorinternus L5, S1
Lateral rotation of the extended hip
joint; abduction of flexed hip
Piriformis – triangular Anterior surface of sacrum between
anterior sacral foramina
Medial side of superiorborder of greatertrochanter of femur
Branches from L5, S1 and S2
Lateral rotation of the extended hip
joint; abduction of flexed hip
MUSCLES OF THE PELVIC DIAPHRAGMMUSCLE ORIGIN INSERTION INNERVATION ACTION
Levator ani Posterior pubis and ischial spine
(In a line around the pelvic wall beginning on the posterior aspect of
the pubic bone and extending across the obturator internus
muscle as a tendinousarch (thickening of the
obturator internusfascia) to the ischial
spine)
Sacrum and CoccyxThe anterior part is
attached to the superior surface of the
perineal membrane; the posterior part
meets its partner on the other side at the
perineal body, around the anal canal, and
along the anococcygealligament
Branches direct from the ventral ramus of S4, and
by the inferior rectal branch of the pudendal
nerve (S2 to S4)
Elavates anus,supports pelvic
viscera, contributesto the formation of
the pelvic floor, reinforces the external anal
sphincter and in women, functions as a vaginal sphincter
Coccygeus Ischial spine and pelvic surface of the
sacrospinous ligament
Lateral margin ofcoccyx, and relatedborder of sacrum
Branches from the anterior rami of S3 and S4
Contributes to the formation of the
pelvic floor, which supports the pelvic viscera; pulls coccyx
MUSCLES WITHIN THE DEEP PERINEAL POUCHMUSCLE ORIGIN INSERTION INNERVATION ACTION
Deep transverse perineal Medial aspect of ischialramus
Perineal body Perineal branches of the pudendal nerve (S2 to S4)
Stabilizes the position of the perineal body
Compressor urethrae (in women only)
Ischiopubic ramus on each side
Blends with partner onother side anterior tothe urethra
Perineal branches of the pudendal nerve (S2 to S4)
Functions as an accessory sphincter of
the urethra
Sphincter urethrovaginalis (in
women only)
Perineal body Passes forward lateral tothe vagina to blend withpartner on other sideanterior to the urethra
Perineal branches of the pudendal nerve (S2 to S4)
Functions as an accessory sphincter of the urethra (also may facilitate closing the
vagina)
MUSCLES WITHIN THE DEEP PERINEAL POUCHMUSCLE ORIGIN INSERTION INNERVATION ACTION
External urethral sphincter
From the inferior ramus of the pubis on each
side and adjacent walls of the deep perineal
pouch
Surrounds membranous part of urethra
Perineal branches of the pudendal nerve (S2 to S4)
Compresses the membranous urethra;
relaxes during micturition
Deep transverse perineal Medial aspect of ischialramus
Perineal body Perineal branches of the pudendal nerve (S2 to S4)
Stabilizes the position of the perineal body
Compressor urethrae (in women only)
Ischiopubic ramus on each side
Blends with partner onother side anterior tothe urethra
Perineal branches of the pudendal nerve (S2 to S4)
Functions as an accessory sphincter of
the urethra
Sphincter urethrovaginalis (in
women only)
Perineal body Passes forward lateral tothe vagina to blend withpartner on other sideanterior to the urethra
Perineal branches of the pudendal nerve (S2 to S4)
Functions as an accessory sphincter of the urethra (also may facilitate closing the
vagina)
MUSCLES IN GASTROINTESTINAL SYSTEMMUSCLE ORIGIN INSERTION INNERVATION ACTION
External anal sphincter Coccyx Central tendon of perineum
inferior rectal nerves (from the pudendal
nerve)
Keeps orifice of anal canal closed
Puborectalis posterior aspect of the body of the pubis
unites with thepuborectalis m. of otherside posterior to therectum
branches of the ventral primary rami of spinal
nerves S3-S4
draws the distal rectum forward and
superiorly; aids in voluntary retention of
feces
Internalanal sphincter
encircles the anal canal encircles the anal canal parasympathetic fibers from S4
constricts the anal canal
Iliococcygeus arcus tendineus levatorani and the ischial spine
anococcygeal raphe and the coccyx
branches of the ventral primary rami of spinal
nerves S3-S4
elevates the pelvic floor
MUSCLES OF THE UPPER EXTREMITYMUSCLE ORIGIN INSERTION INNERVATION ACTION
Trapezius Superior nuchal line, external occipital protuberance, medial
margin of the ligamentumnuchae, spinous processes of
CVII to TXII and the related supraspinous ligaments
Superior edge of the crest of the spine of the scapula,
acromion, posterior border of lateral one-third of clavicle
Motor spinal part of accessory nerve (XI). Sensory
(proprioception) anterior rami of C3 and C4
Powerful elevator of the scapula; rotates the scapula
during abduction of humerus above horizontal;
middle fibers retract scapula; lower fibers
depress scapula
Deltoid Inferior edge of the crest of the spine of the scapula,
lateral margin of the acromion, anterior border of lateral one-
third of clavicle
Deltoid tuberosity of humerus Axillary nerve (C5, C6) Major abductor of arm (abducts arm beyond initial 15° done by supraspinatus);
clavicular fibers assist in flexing the arm; posterior fibers assist in extending
the arm
Levator scapulae Transverse processes of CI and CII vertebrae and posterior
tubercles of transverse processes of CIII and CIV
vertebrae
Posterior surface of medialborder of scapula fromsuperior angle to root of spineof the scapula
Branches directly from anterior rami ofC3 and C4spinal nerves and by branches (C5) from the
dorsal scapular nerve
Elevates the scapula
Rhomboid minor Lower end of ligamentumnuchae and spinous processes
of CVII and TI vertebrae
Posterior surface of medialborder of scapula at the rootof the spine of the scapula
Dorsal scapular nerve (C4, C5) Elevates and retracts the scapula
Rhomboid major Spinous processes of TII–TV vertebrae and intervening
supraspinous ligaments
Posterior surface of medialborder of scapula from theroot of the spine of thescapula to the inferior angle
Dorsal scapular nerve (C4, C5) Elevates and retracts the scapula
MUSCLES OF THE UPPER EXTREMITYMUSCLE ORIGIN INSERTION INNERVATION ACTION
Supraspinatus
Medial two-thirds of the supraspinous fossa of the
scapula and the deep fascia that covers the muscle
Most superior facet on the greater tubercle of the
humerusSuprascapular nerve (C5, C6)
Rotator cuff muscle; initiation of abduction of
arm to 15° at glenohumeral joint
Infraspinatus
Medial two-thirds of the infraspinous fossa of the
scapula and the deep fascia that covers the muscle
Middle facet on posteriorsurface of the greatertubercle of the humerus
Suprascapular nerve (C5, C6)Rotator cuff muscle;
lateral rotation of arm at the glenohumeral joint
Teres minor
Upper two-thirds of a flattened strip of bone on
the posterior surface of the scapula immediately
adjacent to the lateral border of the scapula
Inferior facet on theposterior surface of thegreater tubercle of thehumerus
Axillary nerve (C5, C6)Rotator cuff muscle;
lateral rotation of arm at the glenohumeral joint
Teres major
Elongate oval area on the posterior surface of the
inferiorangle of the scapula
Medial lip of theintertubercular sulcus on theanterior surface of thehumerus
Inferior subscapular nerve (C5, C6,C7)
Medial rotation and extension of the arm at the glenohumeral joint
Long head of triceps brachiiInfraglenoid tubercle on
scapula
Common tendon of insertionwith medial and lateralheads on the olecranonprocess of ulna
Radial nerve (C6, C7, C8)
Extension of the forearm at the elbow joint;
accessory adductor and extensor of the arm at the
glenohumeral joint
MUSCLES OF THE UPPER EXTREMITYMUSCLE ORIGIN INSERTION INNERVATION ACTION
Pectoralis major
Clavicular head—anterior surface of medial half of
clavicle; sternocostalhead—anterior surface of sternum; first seven costal cartilages; sternal end of sixth rib; aponeurosis of
external oblique
Lateral lip of intertubercular sulcus of
humerus
Medial and lateral pectoral nerves; clavicular head (C5,
C6); sternocostal head (C6, C7, C8, T1)
Flexion, adduction, and medial rotation of arm at glenohumeral joint;
clavicular head—flexion of extended arm;
sternocostal head—extension of flexed arm
SubclaviusFirst rib at junction
between rib and costal cartilage
Groove on inferior surfaceof middle one-third ofclavicle
Nerve to subclavius (C5, C6)
Pulls tip of shoulder down; pulls clavicle medially to stabilize sternoclavicular joint
Pectoralis minor
Anterior surfaces and superior borders of ribs III to V; and from deep fascia
overlying the related intercostal spaces
Coracoid process ofscapula (medial border andupper surface)
Medial pectoral nerve (C5, C6,C7, C8, T1)
Pulls tip of shoulder down; protracts scapula
Serratus anterior
Lateral surfaces of upper 8–9 ribs and deep fascia
overlying the related intercostal spaces
Costal surface of medialborder of scapula
Long thoracic nerve (C5, C6, C7)
Protraction and rotation of the scapula; keeps
medial border and inferior angle of scapula opposed to thoracic wall
MUSCLES OF THE UPPER EXTREMITYMUSCLE ORIGIN INSERTION INNERVATION ACTION
SubscapularisMedial two-thirds of
subscapular fossaLesser tubercle of humerus
Upper and lower subscapular nerves (C5, C6, (C7))
Rotator cuff muscle; medial rotation of the
arm at the glenohumeral joint
Teres major
Elongate oval area on the posterior surface of the
inferior angle of the scapula
Medial lip of theintertubercular sulcus onthe anterior surface of thehumerus
Lower subscapular nerve (C5, C6, C7)
Medial rotation and extension of the arm at the glenohumeral joint
Latissimus dorsi
Spinous processes of lower six thoracic vertebrae and
related interspinousligaments; via the
thoracolumbar fascia to the spinous processes of
the lumbar vertebrae, related interspinous
ligaments, and iliac crest; lower 3–4 ribs
Floor of intertubercularsulcus
Thoracodorsal nerve (C6, C7, C8)
Adduction, medial rotation, and extension
of the arm at the glenohumeral joint
Long head of triceps brachii
Infraglenoid tubercle on scapula
Common tendon ofinsertion with medial andlateral heads on theolecranon process of ulna
Radial nerve (C6, C7, C8)
Extension of the forearm at the elbow
joint; accessory adductor and extensor
of the arm at the glenohumeral joint
MUSCLES OF THE UPPER EXTREMITY
MUSCLE ORIGIN INSERTION INNERVATION ACTION
Biceps brachii
Long head—supraglenoid tubercle
of scapula; short head—apex of coracoid
process
Tuberosity of radiusMusculocutaneous nerve
(C5, C6)
Powerful flexor of the forearm at the elbow joint and supinator of
the forearm; accessory flexor of
the arm at the glenohumeral joint
CoracobrachialisApex of coracoid
process
Linear roughening onmidshaft of humerus onmedial side
Musculocutaneous nerve ( C5, C6, C7)
Flexor of the arm at the glenohumeral joint;
adducts arm
MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION)
MUSCLE ORIGIN INSERTION INNERVATION ACTION
PiriformisAnterior surface of sacrum
between anterior sacral foraminaMedial side of superior border of greater trochanter of femur
Branches from S1 andS2Laterally rotates the extended
femur at hip joint; abducts flexed femur at hip joint
Obturator internus
Anterolateral wall of true pelvis; deep surface of obturator
membrane and surrounding bone
Medial side of greater trochanterof femur
Nerve to obturator internus (L5,S1)Laterally rotates the extended
femur at hip joint; abducts flexed femur at hip joint
Gemellus superior External surface of ischial spine
Along length of superior surfaceof the obturator internus tendonand into the medial side ofgreater trochanter of femur withobturator internus tendon
Nerve to obturator internus (L5,S1)Laterally rotates the extended
femur at hip joint; abducts flexed femur at hip joint
Gemellus inferiorUpper aspect of ischial
tuberosity
Along length of inferior surfaceof the obturator internus tendonand into the medial side ofgreater trochanter of femur withobturator internus tendon
Nerve to quadratus femoris (L5, S1)Laterally rotates the extended
femur at hip joint; abducts flexed femur at hip joint
Quadratus femorisLateral aspect of the ischium just
Quadrate tubercle on theintertrochanteric crest of the Nerve to quadratus femoris (L5, S1)
Laterally rotates femur at hip
MUSCLES OF THE LOWER EXTREMITY (GLUTEAL REGION)
MUSCLE ORIGIN INSERTION INNERVATION ACTION
Gemellus inferiorUpper aspect of ischial
tuberosity
Along length of inferior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon
Nerve to quadratus femoris (L5, S1)Laterally rotates the extended
femur at hip joint; abducts flexed femur at hip joint
Quadratus femorisLateral aspect of the ischium just anterior to the ischial tuberosity
Quadrate tubercle on theintertrochanteric crest of theproximal femur
Nerve to quadratus femoris (L5, S1)Laterally rotates femur at hip
joint
Gluteus minimusExternal surface of ilium
between inferior and anterior gluteal lines
Linear facet on the anterolateralaspect of the greater trochanter
Superior gluteal nerve (L4, L5, S1)
Abducts femur at hip joint; holds pelvis secure over
stance leg and prevents pelvic drop on the opposite swing
side during walking; medially rotates thigh
Gluteus mediusExternal surface of ilium
between anterior and posterior gluteal lines
Elongate facet on the lateralsurface of the greater trochanter
Superior gluteal nerve (L4, L5, S1)
Abducts femur at hip joint; holds pelvis secure over
stance leg and prevents pelvic drop on the opposite swing
side during walking; medially rotates thigh
Fascia covering gluteus medius,
MUSCLES OF THE LOWER EXTREMITY (ANTERIOR COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION
Psoas major
Posterior abdominal wall (lumbar transverse processes,
intervertebral discs, and adjacent bodies from TXII to LV and
tendinous arches between these points)
Lesser trochanter of femur Anterior rami (L1, L2, L3)Flexes the thigh at the hip
joint
IliacusPosterior abdominal wall (iliac
fossa)Lesser trochanter of femur Femoral nerve (L2, L3)
Flexes the thigh at the hip joint
Vastus medialis
Femur—medial part of intertrochanteric line, pectineal
line, medial lip of the lineaaspera, medial supracondylar
line
Quadriceps femoris tendon andmedial border of patella
Femoral nerve (L2,L3, L4)Extends the leg at the knee
joint
Vastus intermediusFemur—upper two-thirds of anterior and lateral surfaces
Quadriceps femoris tendon,lateral margin of patella, andlateral condyle of tibia
Femoral nerve (L2,L3, L4)Extends the leg at the knee
joint
Vastus lateralis
Femur—lateral part of intertrochanteric line, margin of
greater trochanter, lateral margin of gluteal tuberosity, lateral lip of
the linea aspera
Quadriceps femoris tendon andlateral margin of patella
Femoral nerve (L2,L3, L4)Extends the leg at the knee
joint
Rectus femoris
Straight head originates from the anterior inferior iliac spine;
reflected head originates from the ilium just superior to the
acetabulum
Quadriceps femoris tendon Femoral nerve (L2, L3, L4)Flexes the thigh at the hip
joint and extends the leg at the knee joint
Sartorius Anterior superior iliac spineMedial surface of tibia justinferomedial to tibial tuberosity
Femoral nerve (L2, L3)Flexes the thigh at the hip
joint and flexes the leg at the
MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION
Gracilis
A line on the external surfaces of the body of the pubis, the inferior pubic ramus, and the ramus of the ischium
Medial surface of proximal shaft of tibia
Obturator nerve (L2, L3)Adducts thigh at hip
joint and flexes leg at knee joint
Pectineus
Pectineal line (pectenpubis) and adjacent
bone of pelvis
Oblique line extendingfrom base of lessertrochanter to lineaaspera on posteriorsurface of proximalfemur
Femoral nerve (L2, L3)Adducts and flexes
thigh at hip joint
Adductor longus
External surface of body of pubis (triangular depression inferior to pubic crest and lateral to pubic
symphysis)
Linea aspera on middleone-third of shaft offemur
Obturator nerve (anterior division) (L2, L3, L4)
Adducts and medially rotates thigh at hip
joint
Adductor brevis
External surface of body of pubis and
inferior pubic ramus
Posterior surface ofproximal femur andupper one-third of lineaaspera
Obturator nerve (L2, L3)Adducts and medially
rotates thigh at hip joint
Adductor part—ischiopubic ramus
Posterior surface ofproximal femur, lineaaspera, medial
Obturator nerve (L2, L3, L4)
Adducts and medially rotates thigh at hip
joint
MUSCLES OF THE LOWER EXTREMITY (MEDIAL COMP. THIGH)MUSCLE ORIGIN INSERTION INNERVATION ACTION
Biceps
Long head –inferomedial part of the
upper area of the ischial tuberosity; short
head – lateral lip of linea aspera
Head of fibula Sciatic nerve (L5, S1, S2]
Flexes leg at knee joint; extends and
laterally rotates thigh at hip joint and
laterally rotates leg at knee joint
SemitendinosusInferomedial part of the
upper area of the ischial tuberosity
Medial surface ofproximal tibia
Sciatic nerve (L5,S1,S2)
Flexes leg at knee joint and extends thigh at hip joint;
medially rotates thigh at hip joint and leg at
knee joint
SemimembranosusSuperolateral
impression on the ischial tuberosity
Groove and adjacentbone on medial andposterior surface ofmedial tibial condyle
Sciatic nerve (L5, S1,S2)
Flexes leg at knee joint and extends thigh at hip joint;
medially rotates thigh at hip joint and leg at
knee joint