AFA exam 1 Flashcards

1
Q

descending part of trapezius

A

Origin - External occipital protuberance, superior nuchal line, nuchal ligament, spinous process of C7

insertion - posterior aspect of lateral one third of clavicle, acromion of scapula

action - elevates, retracts and upwardly rotates the shoulder girdle at acromioclavicular and sternoclavicular joints, extends and laterally flexes head and neck

innervation - accessory nerve, anterior rami of third and fourth cervical nerves

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2
Q

transverse part of trapezius

A

Origin: Spinous processes of C7-T4 vertebrae.
Insertion: Acromion of scapula, medial half of spine of scapula.
Action: Retracts the shoulder girdle at acromioclavicular and sternoclavicular joints.
Innervation: Accessory nerve, anterior rami of third and fourth cervical nerves.

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3
Q

ascending part of trapezius

A

Origin: Spinous processes of T5-T12 vertebrae.
Insertion: Medial half of spine of scapula.
Action: Depresses, retracts, and upwardly rotates the shoulder girdle at AC and SC joints.
Innervation: Accessory nerve, anterior rami of third and fourth cervical nerves.

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4
Q

levator scapulae

A

Origin: Transverse processes of C1-C4 vertebrae
Insertion: Superior angle of scapula, medial border of scapula superior to spine of scapula.
Action: Elevates and down rotates shoulder girdle at AC/SC joints; extends and laterally flexes neck
Innervation: Anterior rami of third and fourth cervical nerves, dorsal scapular nerve (C5).

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5
Q

rhomboid minor + major

A

Origin: Nuchal ligament and spinous processes of C7-T5 vertebrae.
Insertion: Medial border of scapula.
Action: Retracts and downwardly rotates shoulder girdle at AC/SC joints.
Innervation: Dorsal scapular nerve (C4-C5).

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6
Q

subclavius

A

Origin: Superior surface of costal of end of first rib and adjacent first costal cartilage.
Insertion: Inferior surface of the middle one third of clavicle.
Action: Stabilizes clavicle.
Innervation: Nerve to subclavius muscle (C5-C6).

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7
Q

pectoralis minor muscle

A

Origin: Anterior ends of third to fifth ribs.
Insertion: Coracoid process of scapula.
Action: Protracts and downwardly rotates shoulder girdle at AC/SC joints.
Innervation: Medial and lateral pectoral nerves (C5-T1)

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8
Q

pectoralis major

A

Origin: C-head: anterior aspect/medial half of clavicle; SC-head: manubrium, sternal body, the true ribs
and their costal cartilages; A-head: external abdominal oblique aponeurosis.
Insertion: Crest of greater tubercle of humerus OR lateral lip of bicipital groove.
Action: Adducts, medially rotates, and transversely adducts arm at glenohumeral
joint; depresses pectoral (shoulder) girdle at acromioclavicular and sternoclavicular joints.
Innervation: Medial and lateral pectoral nerves (C5-T1).

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9
Q

latissimus dorsi

A

Origin: Spinous processes of T7-L5 via thoracolumbar fascia, ninth to twelfth ribs, iliac crest.
Insertion: Floor of intertubercular sulcus of humerus.
Action: Adducts. medially rotates and extends arm at glenohumeral (shoulder) joint.
Innervation: Thoracodorsal nerve (C6-C8).

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10
Q

teres major

A

Origin: Posterior aspect of inferior angle of scapula.
Insertion: Crest of lesser tubercle of humerus.
Action: Adducts and medially rotates arm at glenohumeral (shoulder) joint.
Innervation: Lower subscapular nerve (C5-C7).

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11
Q

subscapularis

A

Origin: Subscapular fossa of scapula.
Insertion: Lesser tubercle of humerus.
Action: Medially rotates and stabilizes arm at glenohumeral (shoulder) joint.
Innervation: Upper and lower subscapular nerves (C5-C7).

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12
Q

supraspinatus

A

Origin: Supraspinous fossa of scapula.
Insertion: Greater tubercle of humerus.
Action: Abducts and stabilizes arm at glenohumeral (shoulder) joint.
Innervation: Suprascapular nerve (C5-C6).

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13
Q

infraspinatus

A

Origin: Infraspinous fossa of scapula.
Insertion: Greater tubercle of humerus.
Action: Laterally rotates, transversely abducts and stabilizes arm at glenohumeral (shoulder) joint.
Innervation: Suprascapular Nerve (C5-C6).

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14
Q

teres minor

A

Origin: Posterior aspect of superior half of lateral border of scapula.
Insertion: Greater tubercle of humerus.
Action: Laterally rotates, transversely abducts and stabilizes arm at GH (shoulder) joint.
Innervation: Axillary nerve (C5-C6).

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15
Q

Deltoid
(Clavicular,
Acromial +
Scapular Spinal
Part)

A

Origin: Lateral one third of clavicle, Acromion of scapula, Spine of scapula.
Insertion: Deltoid tuberosity of humerus.
Action: Flexes and medially rotates arm at glenohumeral (shoulder) joint.
Innervation: Axillary nerve (C5-C6).

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16
Q

triceps

A

Origin: Long: Infraglenoid tubercle of scapula.
Lateral: Posterior surface of humerus, superior to radial groove.
Medial: Posterior surface of humerus,
inferior to radial groove.
Insertion: Olecranon of ulna and adjacent
antebrachial fascia.
Action: Extends forearm at elbow joint. Long: weak shoulder adduction and extension.
Innervation: Radial nerve (C7).

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17
Q

coracobrachialis

A

Origin: Coracoid process of scapula.
Insertion: Middle third of medial aspect of humerus.
Action: Adducts and flexes arm at
glenohumeral (shoulder) joint.
Innervation: Musculocutaneous nerve (C5-C7).

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18
Q

biceps brachii

A

Origin: SH: Apex of coracoid process of scapula. LH: Supraglenoid tubercle of scapula.
Insertion: Radial tuberosity and antebrachial fascia.
Action: Supinates forearm; flexes forearm at elbow joint, most effectively when the forearm is supinated.
Innervation: Musculocutaneous nerve (C5-C6).

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19
Q

brachialis

A

Origin: Anterior aspect of distal half of humerus.
Insertion: Coronoid process and tuberosity of ulna.
Action: Flexes forearm at elbow joint.
Innervation: Musculocutaneous (C5-C6) and Radial (C7) nerves.

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20
Q

brachioradialis

A

Origin: Superior two thirds of lateral supracondylar ridge of humerus.
Insertion: Lateral aspect of distal part of radius.
Action: Flexes forearm at elbow joint.
Innervation: Radial nerve (C5-C6).

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21
Q

extensor carpi radialis longus

A

Origin: Inferior one third of lateral supracondylar ridge of humerus.
Insertion: Dorsal aspect of base of second metacarpal bone.
Action: Extends hand at radiocarpal (wrist) joint; abducts hand at radiocarpal and
midcarpal joints.
Innervation: Radial nerve (C6-C7).

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22
Q

extensor carpi radialis brevis

A

Origin: Lateral epicondyle of humerus, via common extensor tendon.
Insertion: Dorsal aspect of base of third metacarpal bone.
Action: Extends hand at radiocarpal (wrist) joint; abducts hand at radiocarpal and midcarpal joints.
Innervation: Deep branch of radial nerve (C7-C8) and posterior antebrachial
interosseous nerve (C7-C8).

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23
Q

extensor digitorum

A

Origin: Lateral epicondyle of humerus, via common extensor tendon.
Insertion: Dorsal aspects of bases of both the middle and distal phalanges of the
index, middle, ring, and little fingers.
Action: Extends index, middle, ring, and little fingers.
Innervation: Posterior antebrachial interosseous nerve (C7-C8).

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24
Q

extensor digiti minimi

A

Origin: Lateral epicondyle of humerus, via common extensor tendon.
Insertion: Extensor expansion of little finger.
Action: Extends little finger.
Innervation: Posterior antebrachial interosseous nerve (C7-C8).

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25
extensor carpi ulnaris
Origin: Lateral epicondyle of humerus, via common extensor tendon, and posterior border of ulna. Insertion: Medial aspect of base of fifth metacarpal bone. Action: Extends and adducts hand at radiocarpal (wrist) joint. Innervation: Posterior antebrachial interosseous nerve (C7-C8).
26
Supinator
Origin: Lateral epicondyle of humerus, supinator crest and supinator fossa of ulna. Insertion: Anterior, lateral, and posterior aspects of proximal one third of radius. Action: Supinates forearm at radioulnar joints. Innervation: Posterior antebrachial interosseous nerve (C6-C7).
27
pronator teres
Origin: Medial supracondylar ridge of humerus, via the common flexor tendon, and medial aspect of coronoid process of ulna. Insertion: Middle one third of anterolateral aspect of radius. Action: Pronates forearm at radioulnar joints. Innervation: Median nerve (C6-C7).
28
flexor carpi radialis
Origin: Medial epicondyle of humerus, via common flexor tendon. Insertion: Palmar aspects of bases of second and third metacarpal bones. Action: Flexes hand at radiocarpal (wrist) joint; abducts hand at radiocarpal and midcarpal joints. Innervation: Median nerve (C6-C7).
29
palmaris longus
Origin: Medial epicondyle of humerus, via common flexor tendon. Insertion: Palmar aponeurosis and flexor retinaculum of hand. Action: Flexes hand at radiocarpal (wrist) joint; stabilizes palmar aponeurosis. Innervation: Median nerve (C7-C8).
30
flexor digitorum superficialis
Origin: Medial epicondyle of humerus, via the common flexor tendon, sublime tubercle of ulna, and proximal half of anterior border of radius. Insertion: Palmar aspects of the bodies of middle phalanges of the index, middle, ring, and little fingers. Action: Flexes index, middle, ring, and little fingers. Innervation: Median nerve (C7-T1).
31
flexor carpi ulnaris
Origin: Medial epicondyle of humerus, via common flexor tendon, proximal two thirds of body of ulna, and olecranon of ulna. Insertion: Pisiform, hook of hamate, and palmar aspect of base of fifth metacarpal bone. Action: Flexes and adducts hand at radiocarpal (wrist) joint. Innervation: Ulnar nerve (C7-T1).
32
flexor digitorum profundis
Origin: Medial aspect of coronoid process of ulna and superior three quarters of anterior and medial surfaces of body of ulna. Insertion: Palmar aspects of bases of the distal phalanges of index, middle, ring, and little fingers. Action: Flexes index, middle, ring, and little fingers. Innervation: Medial part: ulnar nerve (C8-T1); Lateral part: anterior interosseous branch of median nerve (C8-T1).
33
flexor pollicis longus
Origin: Anterior surface of radius and adjacent interosseous membrane of forearm. Insertion: Palmar aspect of base of distal phalanx of thumb. Action: Flexes thumb. Innervation: Anterior antebrachial interosseous nerve (C7-T1).
34
pronator quadratus
Origin: Anterior aspect of distal one quarter of ulna. Insertion: Anterior aspect of distal one quarter of radius. Action: Pronates forearm at radioulnar joints. Innervation: Anterior antebrachial interosseous nerve (C7-C8).
35
abductor pollicis longus
Origin: Posterior aspects of proximal half of ulna and middle one third of radius, adjacent interosseous membrane of forearm. Insertion: Lateral aspect of base of first metacarpal bone. Action: Abducts and extends thumb at first carpometacarpal joint. Innervation: Posterior antebrachial interosseous nerve (C7-C8).
36
extensor pollicis brevis
Origin: Posterior surface of distal half of radius and adjacent interosseous membrane of forearm. Insertion: Dorsal aspect of base of proximal phalanx of thumb. Action: Extends thumb. Innervation: Posterior antebrachial interosseous nerve (C7-C8).
37
extensor pollicis longus
Origin: Posterior surface of middle one third of ulna and adjacent interosseous membrane of forearm. Insertion: Dorsal aspect of base of distal phalanx of thumb. Action: Extends thumb. Innervation: Posterior antebrachial interosseous nerve (C7-C8).
38
extensor indicis
Origin: Posterior surface of distal one third of ulna and adjacent interosseous membrane of forearm. Insertion: Extensor expansion of index finger. Action: Extends index finger. Innervation: Posterior antebrachial interosseous nerve (C7-C8).
39
abductor pollicis brevis
Origin: Tubercles of scaphoid and trapezium bones, flexor retinaculum of hand. Insertion: Lateral aspect of base of proximal phalanx of thumb. Action: Abducts thumb at its carpometacarpal joint. Innervation: Recurrent branch of median nerve (C8-T1).
40
opponens pollicis
Origin: Tubercle of trapezium bone and flexor retinaculum of hand. Insertion: Anterolateral aspect of body of first metacarpal bone. Action: Opposes thumb towards other fingers. Innervation: Recurrent branch of median nerve (C8-T1).
41
flexor pollicis brevis
Origin: Tubercle of trapezium bone, palmar aspects of capitate and trapezoid bones, flexor retinaculum of hand. Insertion: Lateral aspect of base of proximal phalanx of thumb. Action: Flexes thumb. Innervation: Superficial head: recurrent branch of median nerve (C8-T1); Deep head: deep branch of ulnar nerve (C8-T1).
42
lumbricals of hand 1-4
Origin: Tendons of flexor digitorum profundus. Insertion: Lateral aspect of extensor expansion of fingers 2-5. Action: Simultaneously flexes metacarpophalangeal joint and extends interphalangeal joints of fingers 2-5. Innervation: 1st and 2nd: Innervation: Common palmar digital branches of median nerve (C8-T1). 3rd and 4th: Deep branch of ulnar nerve (C8-T1).
43
adductor pollicis oblique and transverse head
Origin: OH: Palmar aspects of capitate bone and bases of second and third metacarpal bones. TH: Palmar aspect of body of third metacarpal bone. Insertion: Medial aspect of base of proximal phalanx of thumb. Action: Adducts thumb at its carpometacarpal joint. Innervation: Deep branch of ulnar nerve (C8-T1).
44
abductor digiti minimi
Origin: Pisiform bone and tendon of flexor carpi ulnaris. Insertion: Medial aspect of base of proximal phalanx of little finger. Action: Abducts little finger at its metacarpophalangeal joint. Innervation: Deep branch of ulnar nerve (C8-T1).
45
flexor digiti minimi
Origin: Hook of hamate bone and flexor retinaculum of hand. Insertion: Medial aspect of base of proximal phalanx of little finger. Action: Flexes little finger at its metacarpophalangeal joint. Innervation: Deep branch of ulnar nerve (C8-T1).
46
opponens digiti minimi
Origin: Hook of hamate bone and flexor retinaculum of hand. Insertion: Medial aspect of fifth metacarpal bone. Action: Opposes little finger towards thumb. Innervation: Deep branch of ulnar nerve (C8-T1).
47
palmar inerossei 1-3
Origin: Sides of each metacarpal facing the mid-axis (metacarpal 3) of the hand Insertion: Extensor expansion of proximal phalanx fingers 2-4 on side opposite mid-axis of hand (not on finger 3). Action: Adducts ring finger at its metacarpophalangeal joint; simultaneously flexes metacarpophalangeal joint and extends interphalangeal joints of fingers 2-5. Innervation: Deep branch of ulnar nerve (C8-T1).
48
dorsal interossei of hand 1-4
Origin: Sides of metacarpals Insertion: Base of proximal phalanx and extensor expansion of fingers 2-4 on side opposite mid-axis of hand but on BOTH sides of finger 3. Action: Medially abducts fingers 2-5 at the metacarpophalangeal joint; simultaneously flexes metacarpophalangeal joint and extends interphalangeal joints of fingers 2-5. Innervation: Deep branch of ulnar nerve (C8-T1).
49
occipitofrontalis (epicranius)
Origin: Superior nuchal line of occipital bone. Insertion: Skin of eyebrows and root of nose. Action: Raises eyebrows and wrinkles forehead. Draws scalp backwards. Innervation: Posterior auricular nerve and temporal branches of facial nerve (CN VII).
50
nuccinator
Origin: Alveolar processes of maxilla and mandible, pterygomandibular raphe. Insertion: Angle of mouth. Action: Compresses cheeks. Innervation: Buccal branches of facial nerve (CN VII).
51
obicularis oris
Origin: Vermillion line. Insertion: Skin and fascia of lips. Action: Compresses and protrudes lips. Innervation: Buccal and marginal mandibular branches of facial nerve (CN VII).
52
temporalis
Origin: Temporal fossa and fascia. Insertion: Coronoid process and ramus of mandible. Action: Elevates and retracts mandible. Innervation: Anterior and posterior deep temporal nerves (CN V3).
53
masseter
Origin: Inferior aspect of zygomatic arch. Insertion: Lateral aspect of ramus of mandible. Action: Elevates mandible; assists in protraction of mandible. Innervation: Masseteric nerve (CN V3).
54
medial pterygoid
Origin: Medial surface of lateral pterygoid plate of sphenoid bone. Maxillary tuberosity; pyramidal process of palatine bone. Insertion: Medial surface of ramus and angle of mandible. Action: Laterally moves and protracts mandible Innervation: Nerve to medial pterygoid muscle (CN V3).
55
lateral pterygoid
Origin: Lateral aspect of lateral pterygoid plate of sphenoid bone. Infratemporal surface and infratemporal crest of greater wing of sphenoid bone. Insertion: Neck of mandible. Action: Laterally moves and protracts mandible. Innervation: Nerve to lateral pterygoid muscle (CN V3).
56
sternocleidomastoid
Origin: Anterior Surface of manubrium of sternum. Medial one third of clavicle. Insertion: Mastoid process of temporal bone and superior nuchal line of occipital bone. Action: Flexes and laterally flexes neck; rotates head. Innervation: Accessory nerve (CN XI); proprioceptive fibers from anterior rami second to fourth cervical nerves (C2-C4).
57
sternohyoid
Origin: Sternal end of clavicle and posterior surface of manubrium of sternum. Insertion: Inferior border of hyoid bone. Action: Depresses hyoid bone. Innervation: Ansa cervicalis (C1-C3), from anterior rami of cervical plexus.
58
scalenus anterior
Origin: Anterior tubercles of transverse processes of C3-C6 vertebrae. Insertion: Scalene tubercle of first rib. Action: Flexes, rotates, and laterally flexes neck; elevates first rib. Innervation: Anterior rami of fourth to sixth cervical nerves (C4-C6).
59
scalenus medius
Origin: Posterior tubercles of transverse processes of C2-C7 vertebrae. Insertion: Superior surface of first rib. Action: Laterally flexes neck; elevates second rib. Innervation: Anterior rami of fourth to sixth cervical nerves (C4-C6).
60
Scalenus posterior
Origin: Posterior tubercles of transverse processes of C4-C6 vertebrae. Insertion: External surface of second rib. Action: Laterally flexes neck; elevates second rib. Innervation: Anterior rami of fourth to sixth cervical nerves (C4-C6).
61
longus capitis
Origin: Anterior tubercles of transverse processes of C3-C6 vertebrae. Insertion. Basilar part of occipital bone. Action: Flexes head. Innervation: Anterior rami of first to third cervical nerves (C1-C3).
62
longus colli
Origin: Anterior aspects of lower cervical/upper thoracic vertebrae. Insertion: Anterior aspects of upper cervical vertebrae. Action: Flexes and rotates neck at cervical vertebral joints. Innervation: Anterior rami of second to sixth cervical nerves (C2-C6).
63
rectus capitis posterior minor
Origin: Posterior arch of atlas (C1). Insertion: Inferior nuchal line of occipital bone and adjacent area. Action: Extends head. Innervation: Suboccipital nerve (posterior ramus of first cervical nerve).
64
rectus capitis posterior major
Origin: Spinous process of axis (C2). Insertion: Inferior nuchal line of occipital bone. Action: Rotates and extends head. Innervation: Suboccipital nerve (posterior ramus of first cervical nerve).
65
obliquus capitis inferior
Origin: Spinous process of axis (C2). Insertion: Transverse process of atlas (C1). Action: Rotates head. Innervation: Suboccipital nerve (posterior ramus of first cervical nerve).
66
obliquus capitis superior
Origin: Transverse process of atlas (C1). Insertion: Between superior and inferior nuchal lines of occipital bone. Action: Laterally flexes and extends head. Innervation: Suboccipital nerve (posterior ramus of first cervical nerve).
67
splenius capitis
Origin: Nuchal ligament and spinous processes of C7-T3 vertebrae. Insertion: Mastoid process of temporal bone; lateral one third of superior nuchal line of occipital bone. Action: Rotates and extends head. Innervation: Posterior rami of second and third cervical nerves.
68
semispinalis capitis
Origin: Superior articular processes of lower C (C4-C7) vertebrae; transverse processes of upper T (T1-T6) vertebrae. Insertion: Area located between superior inferior nuchal lines of occipital bone. Action: Extends and rotates the head. Innervation: Greater occipital (C2) and third cervical nerves.
69
illicostalis thoracis and lumborum
Origin: Iliac crest; posterolateral aspect of sacrum. Angles of lower (seventh to twelfth) ribs. Insertion: Transverse processes of lumbar (L1-L4) vertebrae; angles of first to tenth ribs. Action: Extends and laterally flexes trunk. Innervation: Lateral branches of posterior rami of thoracic and lumbar nerves.
70
longissimus thoracis, colli and capitis
Origin: T = Spinous processes of lumbar (L1-L5) vertebrae, dorsal surface of sacrum, and Iliac crest. C+C = Transverse processes of cervical and thoracic (C4-T6) vertebrae. Insertion: T = Transverse processes of lumbar and thoracic vertebrae, and second to twelfth ribs. C + C = Posterior tubercles of transverse processes of middle C (C2-C6) vertebrae. Mastoid process of temporal bone. Action: Extends and laterally flexes trunk and neck. Extends, rotates and laterally flexes head. Innervation: Lateral branches of posterior rami of thoracic and lumbar nerves.
71
spinalis thoracis and colli
Origin: Spinous processes of C, T and L (C7-L3) vertebrae. Insertion: Spinous processes of C2-T8 vertebrae. Action: Extends and laterally flexes trunk and neck. Innervation: Posterior rami of thoracic and upper lumbar nerves.
72
multifidus
Origin: Posterior superior iliac spine, dorsal surface of sacrum, mammillary processes of lumbar vertebrae, transverse processes of thoracic vertebrae, articular processes of mid to lower cervical (C4-C7) vertebrae. Insertion: Spinous processes of lumbar, thoracic, and cervical vertebrae. Action: Extends neck and trunk; stabilizes vertebral column. Innervation: Medial branches of posterior rami of cervical, thoracic, and lumbar nerves.
73
interspinales intertransversaril rotatores
Origins: IS: Superior aspects of spinous processes C3-L5. IT: Inferior aspects of transverse processes C2-T1 and T10-L4. R: Transverse processes of thoracic vertebrae. Insertions: IS: Inferior aspects of spinous processes of C2-L4. IT: Superior aspects of transverse processes of C1-C7 and T11-L5 R: Laminae and spinous processes of thoracic vertebrae one vertebral segment above. Action: Extends and rotates trunk: stabilizes vertebral column. Innervation: Posterior rami of adjacent cervical, thoracic and lumbar nerves.
74
external intercostals
Origin: Inferior borders of first to eleventh ribs. Insertion: Superior borders of ribs immediately below origin sites. Action: Elevate ribs at their costovertebral joints; provide structural support to intercostal spaces. Innervation: Adjacent intercostal nerves (anterior rami of thoracic nerves).
75
internal intercostal
Origin: Inferior borders of first to eleventh ribs and their adjacent costal cartilages. Insertion: Superior borders of ribs and costal cartilages immediately below origin sites. Action: Depress ribs at their costovertebral joints; provide structural support to intercostal spaces. Innervation: Adjacent intercostal nerves (anterior rami of thoracic nerves).
76
diaphragm
Origin: Xiphoid process, internal surfaces of seventh to twelfth costal cartilages and adjacent ribs, medial and lateral arcuate ligaments, L1-L3 vertebrae. Insertion: Central tendon. Action: Primary muscle of inspiration. Innervation: Motor: phrenic nerves (C3-C5); Sensory: phrenic nerves and lower intercostal nerves.
77
quadratus lumborum
Origin: Posterior half of iliac crest and iliolumbar ligament. Insertion: Inferior border of twelfth rib, transverse processes of (L1-4) lumbar vertebrae. Action: Extends and laterally flexes trunk; stabilizes twelfth rib during inspiration. Innervation: Anterior rami of twelfth thoracic and first to fourth lumbar nerves.
78
rectus abdominis
Origin: Pubic crest and symphysis. Insertion: Xiphoid process and costal cartilages of fifth to seventh ribs. Action: Flexes trunk; compresses and provides structural support to adjacent abdominal structures. Innervation: Anterior rami of 6-12 thoracic nerves.
79
external abdominal oblique
Origin: External surfaces and inferior borders of mid-lower (5-12) ribs. Insertion: Anterior superior iliac spine, anterior half of iliac crest, pubic crest, pubic tubercle, linea alba. Action: Flexes, laterally flexes, and rotates trunk; compresses and provides structural support to adjacent abdominal structures. Innervation: Anterior rami of 7-12 thoracic nerves.
80
internal abdominal oblique
Origin: Thoracolumbar fascia, iliac crest, inguinal ligament. Insertion: Inferior margins of lower (10-12) ribs and adjacent costal cartilages, linea alba, pecten pubis. Action: Flexes, laterally flexes, rotates trunk; compresses and provides structural support Innervation: Anterior rami of 7-12 thoracic nerves, iliohypogastric and ilioinguinal nerves.
81
transverse abdominis
Origin: Costal cartilages of mid-lower (7-12) ribs, thoracolumbar fascia, iliac crest, and inguinal ligament. Insertion: Linea alba, pubic crest. And pecten pubis. Action: Compresses and provides structural support to adjacent abdominal structures. Innervation: Anterior rami of seventh to twelfth thoracic nerves, iliohypogastric and ilioinguinal nerves.
82
occygeus
Origin: Ischial spine. Insertion: Anterolateral aspects of sacrum and coccyx. Action: Provides structural support to adjacent pelvic structures. Innervation: Anterior rami of fourth and fifth sacral nerves (S4-S5).
83
puboanalis (puboreactalis)
Origin: Posterior aspect of body of pubis. Insertion: Fibers surround posterior aspect of anorectal junction. Action: Provides structural support to adjacent pelvic structures; fecal continence. Innervation: Nerve to levator ani muscle (S3-S4); inferior anal and perineal nerves.
84
pubococcygeus
Origin: Posterior aspect of body of pubis and tendinous arch of levator ani. Insertion: Coccyx, pubococcygeus tendon, perineal body, and lateral walls of vagina in females and prostate in males. Action: Provides structural support to adjacent pelvic structures; urinary and fecal continence. Innervation: Nerve to levator ani muscle (S3-S4); inferior anal and perineal nerves.
85
iliococcygeus
Origin: Ischial spine and tendinous arch of levator ani. Insertion: Coccyx, iliococcygeal raphe, and anococcygeal ligament. Action: Provides structural support to adjacent pelvic structures; fecal continence. Innervation: Nerve to levator ani muscle (S3-S4).
86
transverse + deep perineal
Origin: Ischial tuberosity; ramus of ischium. Insertion: Perineal body. Action: Stabilizes perineal body; provides structural support to adjacent pelvic and perineal structures. Innervation: Perineal nerve via Pudendal (S2-S4).
87
urethral sphincter
Origin: Rami of both left and right ischial bones. Insertion: Fibers encircle urethra (membranous part in Males) Action: Constricts urethra. Innervation: Perineal nerve via Pudendal nerve (S2-S4).
88
bulbospongiosus
Origin: Perineal body; (and median raphe on ventral aspect of penis for male). Insertion: Female: perineal membrane and corpora cavernosa of clitoris; Male: perineal membrane and dorsal aspects of corpus spongiosum and corpora cavernosa of penis. Action: Female: stabilizes perineal body, expresses secretions of greater vestibular glands, and assists in erection of clitoris: Male: stabilizes the perineal body, expels urine and semen from urethra, and assists in erection of penis. Innervation: Perineal nerve via Pudendal (S2-S4).
89
ischiocavernosus
Origin: Ischial tuberosity; ramus of ischium. Insertion: Female: crus of clitoris; Male: crus of penis. Action: Assists in erection of clitoris in females and erection of penis in males. Innervation: Perineal nerve via Pudendal (S2-S4).