Midterm 2 muscles Flashcards
What muscles flex the hand (Extrinsic)
Flexor digitorum superficialis, flexor digitorum profundus
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
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
What muscles extend the hand (extrinsic)
Extensor digitorum, extensor digiti minimi, extensor indicis
Extensor digitorum
O: Lateral epicondyle
I: Extensor expansion of medial 4 digits
A: Extends hand at metacarpophalangeal joints, extends at wrist
Inn: radial
Extensor digiti minimi:
O: Lateral epicondyle
I: Extensor expansion at 5th digit
A: Extend 5th digit at the metacarpophalangeal and interphalangeal joints
Inn: radial
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
What are the actions of the thumb?
Flexion, extension, abduction, adduction, oppisitions, reposition
What muscle flexes the thumb (extrinsic)
Flexor pollicis longus
What muscle abducts the thumb (extrinsic)?
Abductor pollicis longus
What muscles extend the thumb (extrinsic)?
Extensor pollicis longus, extensor pollicis brevis
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
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
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
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
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
