muscular system skeletal muscles and associated connective tissue –skeletal muscle cells=muscle...
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Muscular System
• Skeletal Muscles and associated connective tissue– Skeletal muscle cells=muscle fibers
FUNCTIONS• Produces movement
– (through contraction of cells)• Stabilizes joints and maintains posture
• (through contraction of cells)• Communication
– (through contraction of cells)– Enhances interpersonal communication through facial expression
• Produces body heat – (through high levels of cellular respiration)
Figure 10.2
Figure 10.1
Figure 10.3
Table 10.2
Dark DarkLightLight
striations
Figure 10.8
Figure 10.9
Figure 10.9:
Summary of events initiating and causing contraction
Motor Unit:A motor neuron and all the muscle fibers it innervates
Figure 10.10
Figure 12.10 showing deep fascial compartments
Figure 12.16 showing deep fascial compartments
Figure 12.19 showing deep fascial compartments
Trauma/infection inflammation/swelling + confined space/compartment build up of pressure
a. Pressure on nerves pain & tenderness
b. Compression/obstruction of blood vessels disrupts blood flow
Tissue death (infarction/necrosis)
The following slide has an image of a fasciotomy performed to relieve pressure within an inflamed fascial compartment and diagrams used in lecture to explain the similar basis of carple
tunnel syndrome
Prolonged compromised blood flow
Following slides are descriptions of motor innervations of selected nerves
Motor Cortex: Frontal LobeControls conscious/volunatary muscle activity
Figure 15.11
Figure 15.12
Somatomotor homunculus -- on precentral gyrus -- primary somatomotor cortex
Frontal Lobe
• Primary Somatic Motor Center:– Precentral gyrus /primary motor cortex: – Origin of motor neurons to specific muscles– Contralateral– Contains the motor homunculus, a ‘motor map’ of
the body• Premotor area: anterior to primary motor cortex.
– Motor functions organized before initiation of activity– Including frontal eye field for eye movement
• Broca's area: motor speech- muscle to vocalize
• Frontal lobe and motor control is contralateral: e.g., the right frontral lobe controls movement on the left side of the body
Motor innervations for selected Cranial Nerves V, VII, & XI
Trigeminal Nerve (V)
• Motor Innervation:– Muscles of mastication
(and some of palate and throat)
– Through: • Foramen ovale• Foramen rotundum• Superior orbital fissure
Facial Nerve (VII)• Motor:
– Muscles of facial expression– (and some throat muscles)
– Bell’s (Facial) Palsy– Some branches pass through internal
acoustic meatus and stylomastoid foramen
Accessory Nerve (XI) / a.k.a. spinal accessory nerve
• Motor:– Sternocleidomastoi
d and trapezius– Some pharynx muscles
– Passes through the jugular foramen
Radial Nerve:
Course:• Through axilla, then deep
along posterior humerus then along radius
Motor innervation: • All upper limb extensor
muscles + brachioradialis and
supinator
Factoid: Wrist drop (crutch paralysis):
constant pressure on/in axillary or region or other pressure on nerve can cause damage to nerve preventing wrist extensors from working resulting in “drop” of wrist.
Median Nerve:
Course• Along medial,
anterior humerus, across antecubital region (i.e., elbow pit) into wrist
Motor Innervation: • Pronators, flexors of
wrist and digits & most thumb muscles
• Flex carp rad and deep muscle• Does not innervate brachiorad.
Factoid:Involved with Carple
tunnel Syndrome
Ulnar NerveCourse: • runs on medial arm
and forearm (along ulna)
Motor: • Some wrist flexors
(flexor carpi ulnaris) and intrinsic digit flexors
• And most digit ab/adductors
Factoid:Association w/ “funny
bone”
Femoral Nerve
Course, from lumbar region/plexus across front of iliacus muscle and over the top/front of pubic bone
Motor: • iliopsoas, pectineus,
quadriceps group, & sartorius– Flexion of thigh
and/or extension of knee
Sciatic nerve = tibial nerve + common fibular nerve
Posterior view
anterior view
Tibial (sciatic) Nerve
Course: from sacral plexus, through greater sciatic notch to pass behind the pubis and enter posterior thigh and leg and most of foot
Motor:• Posterior thigh
(hamstrings) and posterior leg
muscles; muscles (those that plantar flex foot and flex toes) flexors
Common Fibular (sciatic) Nerve
Course:• Separates from tibial in
popliteal fossa (knee pit) and innervates anterior and lateral leg and foot
Motor:• Anterior and
lateral leg muscles and to extensors of toes