MSK Flashcards
What nerve innervates the anterior forearm?
Mainly the median nerve (C6-T1)
BUT
lateral part of flexor digitorum profundus and flexor carpi ulnaris are innervated by the ulnar nerve (C7-T1)
What nerve innervated the posterior forearm?
The radial nerve (C5-T1 although most of them include at least C7)
What muscle innervated the anterior upper arm?
Musculocutaneous (C5-C6)
What muscle innervates the posterior upper arm?
The radial nerve (C5-T1 although posterior upper arm only uses C6-C8)
What are the 3 muscles of the upper anterior arm?
Coracobrachialis
Biceps brachii
Brachialis
What are the 2 muscles of the posterior upper arm?
Triceps brachii
Anyone us
What are the muscles of the 1st layer of the anterior forearm?
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
What are the muscles of the 2nd layer of the anterior forearm?
Flexor digitorum superficialis
What are the muscles of the third layer of the anterior forearm?
Flexor digitorum profundus
Flexor pollicis longus
What are the muscles of the fourth and deepest layer of the anterior forearm?
Pronator quadratus
What are the muscles of the superficial layer of the posterior forearm?
Extensor digiti minimi Extensor digitorum Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Anconeus Brachioradialis
What are the muscles of the deep layer of the posterior forearm?
Extensor indices Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Supinator
Where do most of the flexor of the wrist emerge?
Medial epicondyle of humerus EXCEPT pronator quadratus
Where do most of the posterior forearm muscles originate and which don’t fit this pattern?
All the superficial layer originate at the lateral epicondyle of the humerus
What are the intrinsic muscles of the hand and their innervation?
Palmaris brevis. Ulnar nerve
Lumbricals. Lateral 2 = median, medial 2
= ulnar
Interossei (dorsal and palmar). Both ulnar nerve
Opponens pollicis. Median nerve
Abductor pollicis brevis. Median nerve
Flexor pollicis brevis. Median nerve
Opponens digiti minimi. Ulnar nerve
Abductor digiti minimi. “
Flexor digiti minimi brevis “
Adductor pollicis. “
What is the function of the lumbricals and the interossei of the hand?
Lumbricals extend IP joint but flex MCP
Dorsal interossei abduct fingers 2, 3 and 4
Palmar interossei adduct fingers 2, 3 and 4
What type of grip do the 2 types of hand muscle focus on?
Intrinsic - precision grip
Extrinsic - power grip
What order are energy stores used to supply a working muscle?
First few seconds - ATP
Phosphorylation of ADP by CrP using CK
Anaerobic respiration
Aerobic respiration
What are the muscle arrangements and examples of these?
Unipennate (lateral 2 lumbricals, extensor digitorum) Bipennate (medial 2 lumbricals) Multipennate (deltoids) Circular (orbicularis oris) Fusiform (biceps brachii) Convergent (pec major)
What is a fixator muscle?
Muscles which stabilise the action of primer movers at joints that aren’t intending to move.
What is an agonist in terms of muscle?
The prime mover of the joint.
What is an antagonist in terms of muscle?
A muscle which opposes the prime movers
What is a synergist muscle?
One which assists the prime mover by neutralising any extra motion.
What is the fulcrum?
The pivotal point upon a muscular force
What are the classes of movement and give examples?
First class
- force, fulcrum, load
- head movement
Second class
- force, load, fulcrum
- ankle joint
Third class
- fulcrum, force, load
- biceps moving elbow
What are the types of muscle contraction and their features?
Isometric - muscle length stays same, tension is variable
Isotonic - muscle length changes, tension is constant
- -> 2 types
1) . Concentric - muscle shortens to exert a force
2) . Eccentric - muscle lengthens to exert a force
What can measure electrical activity in a muscle?
EMG (electromyograph)
How does feedback from muscles occur?
Proprioreceptors are within muscle fibres forming spindles that are associated with a nerve ending.
The nerve ending can detect force the muscle is exerting and its arrangement in 3D space, and sends this information either via a reflex, or to the brain via spinal cord.
This has a role in fibre recruitment
How can extra muscle fibres be recruited?
1) . Temporal summation
- fire more a.p.
2) . Spatial summation
- activate more neurones
Why do muscles have a baseline tone?
Muscle elasticity
Motor neurone activity
What controls muscle tone?
The motor control centre of the brain.
It receives info from the afferent fibre signals via CNS
What is hypotonia and how may it occur?
Loss of baseline tone of muscle
- damage to supplying nerve (motor neurone)
- damage to spinal cord
- damage to cerebellum
- damage to afferent nerve
- muscle degeneration
What are the “crosstalk” signalling molecules between neurones and muscle?
Cytokines
IGF
Neutrophins
How does nerve damage cause atrophy?
It prevents crosstalk between the neurone and its fibres = no longer stimulated = atrophy.
