9-HAND Flashcards
Function of the hand (4)
- Grasp power
- Pinch precision
- Feel
- Communicate
The hand must have (4)
- Strong mobile framework
- Non-slip, pliable gripping surface
- Strong muscles without bulk
- Sensitivity- external and internal environment for control
Skin: (4)
- Ridges
- Sweat glands
- Fibrous septa
- Fat between septa under pressure * no room for expansion if needed
Finger movements:
Abduction & adduction
Extension & flexion
Difference between extrinsic muscles and intrinsic muscles
Extrinsic originates from the forearm and have long tendons that insert onto the hand whereas intrinsic originates inside the hand onto the hand
Muscles that flex the fingers from the forearm (AKA extrinsic finger flexors)
- Flexor Digitorum Superficialis
2. Flexor Digitorum Profundus
Flexor Digitorum Superficialis
Origin: Medial epicondyle of the humerus, superior half of the anterior border of the radius
Insertion: Shafts of the middle phalanges of digits 2-5
Innervation: Median Nerve (C7 &C8, T1)
Action: Flexes middle phalanges at the PIP joints.
With strong contractions, can also flex MCP joints, and the wrist joint
Flexor Digitorum Profundus
Origin: proximal 3/4 of medial and anterior surfaces of ulna and interosseous membrane
Insertion: Base of the distal phalanx of digits 2-5
Innervation: Medial part: ulnar nerve(C8 & T1); Lateral part: anterior interosseous branch of median nerve (C8 & T1)
Action: Flexes distal phalanges at distal interphalangeal joints of medial four digits.
Assists with flexion of the wrist.
Muscles that extend the fingers from the forearm (AKA extrinsic finger extensors):
- Extensor Digitorum
- Extensor Indicis
- Extensor Digiti Minimi
Extensor Digitorum
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansions of medial four digits
Innervation: Deep Branch of the radial nerve (C7, C8)
Action: Extends medial four digits at metacarpophalangeal joints;
Extends hand at wrist joint
Extensor Digiti Minimi
Origin: Lateral epicondyle of humerus
Insertion: Extensor expansion of 5th digit
Innervation: Deep Branch of the radial nerve (C7 & C8)
Action: Extends the 5th digit at the metacarpophalangeal and interphalangeal joints.
Extensor Indicis (2nd digit)
Origin: Posterior surface of ulna and interosseous membrane
Insertion: Extensor expansion of 2nd digit
Innervation: Posterior interesseous nerve (C7 & C8), the continuation of the deep branch of the radial nerve (C7 & C8)
Action: Extends 2nd digit and helps to extend hand at the wrist joint
Thumb movements:
- Abduction & Adduction
- Extension & flexion
- Opposition & reposition
Muscles acting on the thumb from the forearm (AKA Extrinsic thumb muscles)
- Flexor Pollicis Longus
- Abductor Pollicis Longus
- Extensor Pollicis Longus
- Extensor Pollicis Brevis
Flexor Pollicis Longus
Origin: Anterior surface of radius and adjacent interosseous membrane
Insertion: Base of distal phalanx of thumb
Innervation: anterior interosseous nerve from median nerve (C8 & T1)
Action: Flexes phalanges of 1st digit
Abductor Pollicis Longus
Origin: Posterior surfaces of ulna, radius and interosseous membrane
Insertion: Base of 1st metacarpal
Innervation: Posterior interosseous nerve (C7 & C8), the continuation of the deep branch of the radial nerve
Action: Abducts thumb and extends it at carpometacarpal joint
Extensor Pollicis Longus
Origin: Posterior surface of middle 1/3 ulna and interosseous membrane
Insertion: Base of distal phalanx of thumb
Innervation: Posterior interosseous nerve (C7 & C8), the continuation of the deep branch of the radial nerve
Action:Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints
Extensor Pollicis Brevis
Origin: Posterior surfaces of radius and interosseous membrane
Insertion: Base of proximal phalanx of thumb
Innervation: Posterior interosseous nerve (C7 & C8), the continuation of deep branch of the radial nerve
Action: Extends proximal phalanx of thumb at carpometacarpal joint
What are the intrinsic muscles and how many of each
- Interossei (7)
- Lumbricals (4)
- Thenar (4)
- Hypothenar (4)
Total :19
Interossei muscles (7)
3 palmar & 4 dorsal
Origin: shafts of the metacarpals
Insertion: Bone & extensor expansion of the proximal phalanges of 2-5
Innervation: Deep branch of the ulnar nerve (C8, T1)
Action: adduct & abduct, flex & extend ( at MP and IP joint)
Lumbricals muscles (4)
Origin: (1st and 2nd) Lateral two tendons of FDP (as unipennate muscle)
(3rd and 4th) Medial three tendons of FDP (bipennate muscle)
Insertion: lateral sides of the extensor expansions of the 2nd-5th digits.
Innervation: (1&2) median nerve (C8,T1). (3 &4) deep branch of the ulnar nerve (C8, T1).
Action: Flexes MCPs, and extend IP joints 2nd-5th digits
Hypothenars muscles (=pinky intrinsics)
Origin: medial pillars of flexor retinaculum & retinaculum
Insertion: 1) Abductor digiti minimi
2) Flexor Digiti Minimi
3) Opponents Digiti Minimi
Nerve: Ulnar
Palmaris Brevis (hypothenar)
- Muscle located in the subcutaneous tissue of the hypothenar eminence
- Deepens the hollow of the palm to aid in a palmar grip
- Protects ulnar artery and nerve
Thenar muscles (4)
Origin: lateral pillars flexors retinaculum & retinaculum
Insertion: 1) Abductor pollicis
2) Flexor Pollicis Brevis
3) Opponents Pollicis
Nerve: median
