Lecture 14: Appendicular Muscular System Flashcards
Define/Describe extrinsic appendicular musculature
• Muscles that arise on the axial skeleton or trunk fascia and insert on the girdle or limb. • Begin development from blastemas within the body wall. • Examples: • Latissimus dorsi • Levator scapulae* • Serratus ventralis* • Rhomboideus* • Trapezius# • Sternomastoid# • Cleidomastoid#
# = Branchiomeric * = From Myotomes
Describe intrinsic appendicular muscles
Intrinsic appendicular muscles: • Muscles that arise on a girdle or limb element and insert more distally. • Develop from blastemas from within the limb. • Note that the intrinsic blastemas originate in somites and are innervated by motor fibers from somatic column of spinal cord. • Examples: • Biceps complex • Triceps complex • Digit extensors and flexors • Gluteal complex • Quadriceps complex • Hamstrings
Describe the dorsal extrinsic pectoral muscle, latissimus dorsi
• Most constant dorsal extrinsic appendicular muscle in tetrapods • Arises from superficial fascia in Necturus and inserts on humerus • Pulls humerus caudally • Arises from neural spines via tough fascia in reptiles • Arises from neural spines of thoracic and lumbar vertebrae and from tough fascia in mammals (thoracolumbar fascia) • Major derivative = teres major
Describe the dorsal extrinsic pectoral muscle, trapezius
- Trapezius:
- Derived from fish cucullaris (P)
- May be divided into several components depending on its attachment to scapula:
- Cleidotrapezius
- Acromiotrapezius
- Spinotrapezius
- Innervated by branchiomeric nerves (Cranial nerve XI)
Describe the remaining major dorsal extrinsic pectoral muscles
• Levator scapulae (amniotes): - Two groups of muscles from atlas/basioccipital or from cervical vertebrae to scapular spine • Rhomboideus group (crocodilians and mammals): - From cervical and thoracic vertebrae to dorsal border of scapula • Serratus ventralis (anterior) (amniotes): - From ribs to dorsal border of scapula - See Slides 7-10
Describe the evolution of the pectoral complex and it’s components
Pectoral complex: • Originates from thoracic cage and sternum. • Inserts on humerus. • Major adductor of forelimb. Components: • Pectoralis major. • Pectoralis minor. • Pectoralis descendens: • = pectoantebrachialis. • Xiphihumeralis.
Describe the trends noted in the evolution of pectoral muscles
• Increase in size of latissimus dorsi • Increase in size of pectoralis complex. • Supracoracoideus of amphibians and reptiles: • In mammals = supraspinatus and infraspinatus.
Describe the ventral group of extrinsic pectoral muscles
• Pectoralis and supracoracoideus: • Forearm adductors • Powerful flight muscles in birds • Note that supracoracoid is an intrinsic muscle in mammals. - See Slide 12
Describe the muscles of the scapular sling
• The scapular sling suspends the body between the scapular blades in tetrapods.
• Muscles of the scapular sling:
• Serratus ventralis (anterior):
- From rib cage to medial border of scapula.
- In salamanders:
- = thoraciscapularis
• Levator scapulae:
• From scapula to posterior skull.
• Rhomboids:
- Upper vertebrae to dorso-medial border of scapula.
- See Slide 14
Describe the 4 rotator cuff muscles
Rotator Cuff Muscles (SITS): • Supraspinatus • Infraspinatus • Teres minor • Subscapularis
• Composed of four muscles whose tendons of insertion form a partial “cuff” around the head of the humerus. • Involved in snubbing and rotating head of humerus.
- See Slide 15
May need to memorize shoulder movements and associated muscles.
Not sure yet.
Describe the deltoid complex
• Deltoid complex in salamanders: - Scapulodeltoid. - Procoracohumeralis: Equivalent to teres minor in mammals. - Supracoracoideus: Equivalent to supraspinatus and infraspinatus in mammals. • Major arm (humeral/brachial) abductor. • Arises from pectoral girdle. • Inserts on humerus. • May consist of several muscles: - Clavodeltoid (or cleidodeltoid) - Spinodeltoid - Acromiodeltoid • Single muscle in humans, but has multiple functions.
Review the pectoral-girdle homologies across Necturus, Reptiles, and mammals.
I have no idea how to approach this.
Describe the muscles within the pelvic girdle
In mammals the muscles associated directly with the pelvic girdle can be divided into several compartments, based on location, innervation, vascular supply, and function.
- Divided into the posterior gluteal compartment and the lateral gluteal compartment
What major muscle is found in the posterior gluteal compartment?
Muscles: Gluteus maximus
Action: Hip extension and lateral rotation. Rising, climbing, running (but not walking).
Describe the major muscle groups found in the lateral gluteal compartment
Muscles:
- Gluteus medius.
- Gluteus minimus.
- Tensor fascia latae: Inserts onto iliotibial tract.
- Note that mediusand minimusare the same muscle separated by the superior gluteal nerve.
- Action: Hip abduction with free-swinging limb.
List the 6 deep external rotators of the pelvic girdle
- Piriformis: Leaves pelvis through greater sciatic foramen.
- (Main door for passage of structures from pelvis to thigh.)
- Superior gemellus.
- Obturator internus.
- Inferior gemellus.
- Obturator externus.
- Quadratus femoris.
See slides 22-23, memorizing where the well-mentioned muscles are located.
How are limb segment compartments separated and what does each compartment usually contain a specific set of?
- Limb segments can be divided into compartments.
- These compartments may be separated by fibrous connective tissue septae.
- Each compartment typically has its own:
- Action
- Innervation
- Vascular supply
Describe the anterior brachial compartment.
- Muscle action:
- Flex/supinate forearm
- Flex shoulder
- Contents:
- Biceps brachii
- Brachialis ** (Humeroantebrachialis in salamanders)
- Coracobrachialis
- Innervation:
- Musculocutaneous N.
Describe the posterior brachial compartment
- Muscle action:
- Extend forearm
- Extend shoulder
- Contents:
- Triceps brachii
- Anconeus
- Innervation: Radial N
Describe the anterior antebrachial compartment
- Muscle action:
- Wrist and digit flexion
- Contents:
- Flexor carpi radialis
- Flexor carpi ulnaris
- Flexor digitorum superficialis and profundus
- Palmaris longus
- Flexor digitorum superficialis
- Flexor digitorum profundus
- Pronator teres and quadratus
- Innervation:
- Median nerve
- Ulnar nerve
Describe the posterior antebrachial compartments
- Muscle action: Wrist and digit extension
- Contents:
- Extensor carpi radialis (longus and brevis)
- Extensor carpi ulnaris
- Extensor digitorum
- Separate extensors to thumb and some fingers
- Innervation: Radial nerve
Describe the abductor muscles in the thighs of tetrapods
Gluteal complex: = Iliofemoralis in reptiles.
Describe the Quadriceps Complex of Thigh Muscles of Tetrapods
- Thigh flexor:
- Rectus femoris: = Iliotibialis in reptiles
- Leg extensors:
- Rectus femoris:
- Vasti (lateralis, medialis, intermedius).
- = Femorotibialis in reptiles
Describe the muscles originating from around the obturator foramen
- Obturatus internus: = Ischiotrochantericus in reptiles
- Obturator externus: = Puboischiofemoralis in reptiles
- Quadratus femoris
- Piriformis
Describe the Adductors of the thigh
Adductor complex in mammals:
- Adductor brevis
- Adductor longus
- Adductor magnus = adductor femoris in reptiles.
Describe the thigh extensors and shank flexors in tetrapods
- Gracilis in mammals: = puboischiotibialis in reptiles and salamanders
- Semitendinosus and semimembranosus in mammals: = tibialis externus and internus in reptiles
- Biceps femoris in mammals
Describe the shank (tibial) extensors in tetrapods
Quadriceps in mammals:
Consist of:
- Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius
- = iliotibialis and femorotibialis in reptiles
- Extend shank (tibia)
What was the sartorius in mammals derived from in reptiles?
Sartorius in mammals: = ambiens in reptiles
Describe the main muscles found in the posterior leg?
- Deep Posterior
- Popliteus
- Flexor hallucis longus
- Tibialis posterior
- Superficial posterior:
- Medial and lateral gastrocnemius
- Soleus
- In mammals insert via Achilles on calcaneus In reptiles insert via aponeurosis on the sole of the foot.
Describe the anterior compartments of the leg
- Tibialis anterior
- Extensor digitorum longus
- Peroneus tertius*
- Extensor hallucis longus
- Peroneus is now usually referred to as fibularis.
List the lateral compartments of the leg
- Peroneus longus*
- Peroneus brevis*
- Peroneus is now usually referred to as fibularis.
