What term best describes the relationship between the pronator quadratus and supinator?
Which of the following describes an appearance of red muscular tissue emerging directly from bone rather than being separated from it by an obvious tendon?
receiving calcium ions from the nerve ending
A muscle fiber depends on which of the following for excitation?
In a whiplash injury, the neck undergoes forced hyperextension then hyperflexion, injuring multiple muscles in the neck. Which of the following muscles would be injured during the hyperextension phase of the injury?
sternal manubrium and medial one-third of clavicle; mastoid process and lateral half of superior nuchal line
Which of the following correctly states the origin and insertion of the sternocleidomastoid?
trapezius and serratus anterior
The muscles that laterally rotate and depress the scapula, as in shrugging and lowering the shoulders, are the
It rotates the scapula and depresses the apex of the shoulder.
Which of the following is true regarding the levator scapulae?
ruptured calcaneal tendon
A clinician induces contraction of the gastrocnemius and soleus and notices that the foot does not plantar flex as expected. Which of the following would be a logical diagnosis?
calcaneal tendon; his triceps surae
A heavyset middle-aged insurance salesman who doesn't exercise often accepts his friend's invitation to a pickup basketball game. When attempting a jump shot, he falls to the ground in pain, grasping at the calf of his leg. There is an enormous bulge in his leg immediately below the knee, and he is unable to plantarflex that foot. Most likely he has injured his ___ and the bulge is ___.
An Olympic sprinter readies for a race. After the sound of the starting gun, he propels himself forward from the starting block and immediately grimaces in pain, grabbing for the back of his thigh. Within 48 hours he begins noticing extensive bruising on the back of his thigh extending into the back of the knee. He now has difficulty rising from a seated position and flexing his knee. Bending at the waist generates more pain. Which muscle is likely injured?
After childbirth a woman begins experiencing tremendous pain in her groin, making it difficult for her to walk. She has difficulty walking due to the pain. An X-ray shows a fracture extending from her symphysis pubis to the inferior ramus of the pubis. As a result of the fracture, which group of muscles might be impaired?
A skydiver's parachute fails to deploy. After some struggle, his reserve chute deploys in time to save his life. However, his landing is harder than normal and he feels his knee slightly hyperextend. He shakes it off and goes about his normal routine. Later that day he begins experiencing knee pain. Two days later he notices that his knee "pops" when he crouches and soon discovers he has dislocated his femur on the knee. What muscle was likely injured initially?
Functions of Muscles
Movement, stability, communication, control of body openings and passages, heat production and glycemic control
Spinal Accessory Nerve
Also called the cranial nerve 11 or CNXI - controls motor innervation from the central nervous system to the two muscles of the neck: the sternocleidomastoid muscle and the trapezius muscle
Origin: Manubrium of sternum; medial one-third of clavicle
Insertion: Mastoid process; lateral half of superior nuchal line
Action: Abducts, rotates and flexes head
Innervation: Spinal Accessory Nerve - Cranial Nerve XI
Origin: Transverse processes of vertebrae C1-C4
Insertion: Superior angle to medial border of scapula
Action: Elevates scapula if cervicle vertebrae are fixed; flexes neck laterally if scapula is fixed; retracts scapula and braces shoulder; rotates scapula and dpresses apex of shoulder
Innervation: Spinal nerves C3-C4, and C5 via posterior scapular nerve
Gastrocnemius and Plantar Flexing
The gastrocnemius muscle does not plantar flex when the achilles tendon has been injured. The gastrocnemius muscles are directly attached to the achilles tendon making plantar flexing painful or impossible when the achilles tendon has been compromised.
Alternating light and dark bands of a muscle. A-Bands (anisotropic) are the dark bands that consist of thick filament or myosin. I-Bands (isotropic) are the light bands consisting of thin filament or actin.
Results from one wave of muscle contraction added to another. When a muscle contracts and then partially reflexes when another stimulus occurs.