Chapter 11: Axial Muscles Flashcards
Discuss axial muscles and the basic actions/motions they produce. (7)
- Origins and insertions are on axial skeleton.
- Support/move head and spinal column.
- Assist in food processing (chewing and swallowing).
- Aid breathing.
- Support/protect abdominal and pelvic organs.
- Nonverbal communication (facial expression).
-They do NOT move pectoral/pelvic girdle or limbs.
Define aponeurosis.
Flat sheet of connective tissue used for muscle insertion.
List the 4 paired muscles of mastication.
- Temporalis (elevate/retract)
- Masseter (elevate/protract)
- Lateral pterygoids
- Medial pterygoids
- both 3 & 4 protract and move mandible side to side for chewing
- all innervated by cranial nerve V
List the 4 muscles of the abdominal wall and their function.
1. External oblique
(most superficial of 3 lateral muscles)
2. Internal oblique
(middle of 3 lateral muscles)
3. Transverse abdominis
(deepest of 3 lateral muscles)
4. Rectus abdominis
(anterior, connecting to sternum and pubic bone; divided into 4 muscle segments)
Function:
- Compress and hold abdominal muscles in place
- Flex and stabilize vertebral column
- Laterally flex vertebral column
Discuss the diaphragm. (Structure, Function/How it works)
- Most important muscle for breathing
- Dome shaped muscle
- Separates thoracic and abdominal cavities
- Muscle fibers insert on fibrous central tendon
- Diaphragm contracts, central tendon pulls down which increases dimensions of thoracic cage
- Compresses abdominal cavity which increases abdominal pressure
- Helps blood return to the heart from the lower extremities
What is a hernia?
A portion of the viscera protrudes through a weakened point of the muscular wall of the abdominal cavity.
- If that portion of the intestine swells and becomes trapped, blood flow to that portion of the intestine may diminish causing that part of the ins tine to die; “Strangulated intestinal hernia”
- Painful and can be life threatening
List and describe the 2 types of hernias.
- Inguinal hernia
- most common type
- more likely in males
- rising pressure in abdominal cavity pushes segment of small intestine into canal
- 2 types: direct and indirect - Femoral hernia
- more likely in females
- occurs in upper thigh just inferior to inguinal ligament
- loop of small intestine protrudes through femoral triangle
List and describe the 2 types of Inguinal hernias.
- Direct inguinal hernia
- small intestine protrudes directly through superficial inguinal ring but not all the way down the inguinal canal
- creates bulge in lower anterior abdominal wall - Indirect inguinal hernia
- hernia travels down the entire length of the inguinal canal and may extend into the scrotum
List the 5 groups of axial muscles.
- Muscles of Head/Neck
- Muscles of the Vertebral Column
- Muscles of Respiration
- Muscles of Abdominal Wall
- Muscles of the Pelvic Floor
Muscles of Head/Neck
Originate on either the skull or hyoid
Muscles of Facial Expression
- Originate in superficial fascia or on skull bones
- Insert into superficial fascia of skin
- Contort skin causing it to move
- Mouth is most expressive part of face
- Orbicularis Oris encircles mouth opening and when it contracts, mouth closes
- most innervated by cranial nerve VII (facial nerve)
Extrinsic Eye Muscles
- “Extraocular muscles”
- Move the eyes
- Originate in orbit from common tendinous ring
- Insert onto sclera
- 6 muscles: Innervated by either CN III, IV, or VI
4 rectus muscles: medial, lateral, inferior, superior
2 oblique muscles: inferior, superior
- Innervations, movement - Rectus muscles: medial (CN III) pulls eye medially lateral (CN VI) pulls eye laterally inferior (CN III) pulls eye inferiorly superior (CN III) pulls eye superiorly
Oblique muscles:
inferior (CN III) elevates and turns eye laterally
superior (CN IV) depresses and turns eye laterally
Muscles that Move the Tongue
- Manipulate food in mouth to prepare for swallowing
- Intrinsic and Extrinsic Muscles
- Intrinsic: curl, squeeze, fold tongue for chewing and speaking
- Extrinsic: originate on head and neck structures, insert on tongue; aid tongue movement for speech
Muscles of the Pharynx
- “throat”
- muscles attach or help form tube
- primary muscles here are pharyngeal constrictors (superior, middle, inferior)
- initiate swallowing and force food down into esophagus
- help elevate palate when swallowing
Muscles of Anterior Neck
- suprahyoid muscles: superior to hyoid
- infrahyoid muscles: inferior to hyoid
Muscles of Posterior Neck
- extend head/neck
- trapezius attaches to skull and helps extend head/neck but main function is pectoral girdle movement
Anterolateral Neck Muscles
- provide head/neck flexion
- main muscles:
- sternocleidomastoid
- also causes lateral flexion & rotation of head
- scalenes (anterior, middle, posterior)
- sternocleidomastoid
Muscles of the Vertebral Column
- covered by most superficial back muscles
- 2 major groups:
1. Erector Spinae (3 muscles) - maintain posture
- extend spine
- laterally flex spine
- Transversospinalis
- deep to erector spine
- connect and stabilize vertebra
Muscles of Respiration
- located on the anterior and posterior surfaces of thorax
- covered by superficial muscles
- via contraction and relaxation of these various muscles, inhalation and exhalation occur (moving air in and out of the lungs)
Muscles invovled:
- Serratus posterior superior
- Serratus posterior inferior
- External intercostals
- Internal intercostals
- Transverse thoracis
- Diaphragm
Muscles of the Pelvic Floor
- Pelvic diaphragm: 3 layers of muscles and associated fascia
- Extend from ischium and pubis across pelvic outlet to sacrum and coccyx
- Forms pelvic floor and supports pelvic viscera
- Pelvic floor is composed of layers of muscle that form the urogenital and anal triangles
- Supports organs in the pelvic cavity
Name and briefly describe the 3 erector spine muscles.
“Salt Lake International - SLI”
- Spinalis
- most medial to spine
- cervical and thoracic portions
- insert onto spinous processes of vertebra - Longissimus
- capitis, cervical, and thoracic parts
- between spinals and iliocostalis - Iliocostalis
- most lateral group
- cervical, thoracic, and lumbar parts
