Midterm 2 muscles Flashcards by Ella Mercer

What muscles flex the hand (Extrinsic)

Flexor digitorum superficialis, flexor digitorum profundus

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Flexor Digitorum Superficialis

O: Humeroulnar head: medial epicondyle of the humerus, ulnar collateral ligament, coranoid process of the ulna.
radial heal: Superior half of anterior border of humerus
I: Shafts of middle phalanges 2-5
Action: Flexes middle phalanges at PIP, and can aid flexion at MCP and wrist
Inn: median

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Flexor Digitorum Profundus

O: Proximal 3/4 medial and anterior surfaces of the ulna and interosseous membrane
I: Base of distal phalanx of digits 2-5
A: Flexion of distal phalanx 2-5 at distal interphalangeal joints
Inn: Medial part: ulnar
Lateral part: median

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What muscles extend the hand (extrinsic)

Extensor digitorum, extensor digiti minimi, extensor indicis

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Extensor digitorum

O: Lateral epicondyle
I: Extensor expansion of medial 4 digits
A: Extends hand at metacarpophalangeal joints, extends at wrist
Inn: radial

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Extensor digiti minimi:

O: Lateral epicondyle
I: Extensor expansion at 5th digit
A: Extend 5th digit at the metacarpophalangeal and interphalangeal joints
Inn: radial

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Extensor indicis

O: Posterior surface of the ulna and interosseous membrane
I: Extensor expansion of the 2nd digit
A: Extends 2nd digit, aids extend hand at wrist
Inn: Radial

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What are the actions of the thumb?

Flexion, extension, abduction, adduction, oppisitions, reposition

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What muscle flexes the thumb (extrinsic)

Flexor pollicis longus

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What muscle abducts the thumb (extrinsic)?

Abductor pollicis longus

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What muscles extend the thumb (extrinsic)?

Extensor pollicis longus, extensor pollicis brevis

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Flexor pollicis longus

O: anterior surface of the radius and adjacent interosseous membrane
I: Base of distal phalanx of thumb
A: Flexes thumb
Inn: median

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Abductor pollicis longus

O: Posterior surface of radius, ulna, and interosseous membrane
I: Base of 1st metacarpal
A: Abducts thumb, extends thumb at carpometacarpal joint
Inn: radial

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Extensor pollicis longus

O: Posterior 1/3 surface of ulna and interosseous membrane
I: Base of distal phalanx of thumb
A: Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints
Inn: radial

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Extensor pollicis brevis

O: posterior surfaces of radius and interosseous membrane
I: Proximal phalanx of the thumb
A: extends proximal phalanx of the thumb at carpometacarpal joint
Inn: radial

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Intrinsic hand muscles

interossei, lumbricals, thenars (pinkey), hypothenars (thumb)

Interossei:

7 total
4-dorsal (abducts the hand)
3-palmer (adducts the hand)
Innervated by ulnar nerve

Lumbricals:

4 total
Originates of flexor digitorum profundus
Action: Flexes MCP, extends IP joints 2-5
1-2 innervated by medial
2-4 innervated by ulnar

Hypothenars

4 total:
Abductor digiti minimi
Flexor digiti minimi
Oppens digiti minimi
Palmaris Brevis–acts as protection of structures, aids grip
Innervates ulnar nerve

Thenars

4 total:
Abductor pollicis
Flexor pollicis brevis
Oppens pollicis
Adductor pollicis– 2 heads, transverse and oblique

First 3 innervated by median nerve
Adductor pollicis innervated vy ulnar nerve

What are the muscles of the neck

Sternocleidomastoid, scalenes

Sternocleidomastoid

O: manubrium of sternum, medial portion of clavicle
I: Mastoid process of temporal bone, superior nuchal line
A: Unilaterally: contralateral cervical rotation, ipsilateral flexion of cervical spine
Bilaterally: cervical flexion, assists with forced inhalation–by elevating sternum
Inn: Accessory Nerve

Scalenes

There are three (ant,med,post)
O: Cervical vertebrae (2-7)
I: First and second ribs
Action: Elevation of first and second ribs, lateral flexion of neck. Assists with forced inhalation by elevating first 2 ribs
Ipsilateral lateral flexion

What muscles make up the erector spinae

Illiocostalis, longissiumus, spinalis

Spinalis

Skinniest, most medial. Extends the vertebral column.

Longissimus

Middle muscle, extends the vertebral column. Also laterally flexes vertebral column

Illiocostalis

Most lateral. Aids with extension, lateral flexion.

What is the thoracic portion of the erector spinae?

Longissimus and illiocostalis. They are stabilizers, made of slow twitch fibres. More mitochondrial dense. The line of action is parallel to column. Greatest mechanical advantage for extension.

What is the lumbar portion of the erector spinae.

Longissimus and illiocostalis. More a mix of slow and fast twitch, more force is produced here. Fibres run at a 45 degree angle to the column. Creates the oblique angle and creates a mechanical advantage for creating posterior shear forces to protect from compression and anterior forces.

Multifidus

Run entire length of the column but are small. Extend, but these are localized muscles that allow for corrections at specific joints. Between 2-4 vertebrae.

Rotatores

"Rotators" of the spine. Limited aid to rotation. Have more of a proprioceptive function

Quadratus Lumborum (QL)

O: Illiac crest and illiolumbar ligament. I: Base of 12th rib and transverse processes of lumbar vertebrae. A: Unilateral: lateral flexion of vertebral column Bilateral: depression of rib cage * Research shows its a stabilizer because it doesn't shorten in length during contraction, because lumbar spine is less stable.

Muscles of the abdominal wall:

rectus abdominus, external oblique, internal oblique, transverse abdominus

Rectus Abdominus

O: Crest of pubis I: Costal cartridges of ribs 5-7, xiphoid process A: flexion of lumbar spine

External Oblique

O: Ribs 5-12 I: Illiac crest, pubic tubercle, linea alba A: Contralateral flexion of torso Fibres run down and medial

Internal Oblique

O: Iniguinal ligament, illiac crest, lumbodorsal fascia I: linea alba, ribs 10-12 A: Unilateral: Ipsilateral trunk rotation Bilateral: Compresses abdomen Fibres run up and medial

Transverse abdominis

O: illiac crest, inguinal ligament, thoracolumbar fascia, costal cartildges 7-12 I: Xiphoid process, linea alba, pubic crest A: Compresses abdominal cavity, stabilize spine Fibres run lat-med, across