Lecture 17 - The Neck I Flashcards
Where is the thoracic inlet?
Space bounded by first rib, sternum and T1 vertebra
What is the primary function of the thoracic inlet?
Primary passage way for structures between neck and thorax
What does the vertebral column articulate with?
Occipital bone
What are the main dorsocaudal features of the skull?
External occipital protuberance, nuchal crest, and mastoid process
From rostral to caudal, list the main structures of the ventral portion of the skull?
Foramen lacerum, jugular foramen, hypoglossal canal, occipital condyle
What is the normal number of cervical vertebra?
7
What is the hyoid apparatus? (not function)
Bones running from temporal bones of skull into the neck
What is the function of the hyoid apparatus?
Supporting the tongue, larynx, and pharynx
Where are the laryngeal cartilages?
Cartilages at cranial end of the airway
What is another name for C1?
Atlas
What is the name for the facets on C1 what do they articulate with?
Articular facets, articulate with the occipital condyle
What is a special structure of the C1?
Large transverse processes called wings or Alar processes
What are the palpable landmarks of the atlas and axis?
Wing of atlas and the spinous process of the axis
What are you unable to feel of the axis and atlas in horses and ruminants?
Spine of the axis
Why are you unable to feel the spine of the axis in a horse?
Presence of a fatty crest and the cranial extent of the funicular portion of the ligamentum nuchae
What are the three parts of the hyoid apparatus?
Stylohyoid, basihyoid, and thyrohyoid
What is the stylohyoid?
Articulates with temporal bone (adjacent to the mastoid) via cartilage
What is the cartilage that is associated with the stylohyoid?
Tympanohyoid cart.
What is the basihyoid?
Unpaired, anchored in the musculature of the tongue
What is the thyrohyoid?
Articulates with the thyroid cartilage
What are the four dorsal muscles of the vertebral column?
Spinalis, semispinalis, longissimus, and splenius
What is the origin of the splenius?
T1-T3 spines and cervical midline raphe
What is the insertion of the splenius?
Nuchal crest and mastoid
What nerve innervates the splenius?
Dorsal rami
What is the action of the splenius?
Extend head and neck, some lateral bending of cervical region
What are the three ventral vertebral column muscles?
longus colli, longus capitus, and scalenus
What is another name for the ventral vertebral column muscles?
Hypaxial
Where is the longus colli found?
Cranial thoracic vertebral bodies and cervical vertebral bodies and transverse processes
Where is the longus capitus found?
Lateral to the longus colli from the transverse processes of cervical vertebrae to the ventral part of the skull
Where is the scalenus m. found?
Often a group of three muscles, from caudal cervical vertebrae to cranial ribs
What are the four rectus capitus muscles?
Dorsalis major - Dorsalis minor - Lateralis - Ventralis
What are the two oblique capitus muscles?
Cranialis and Caudalis
What is the function of the capitus muscles?
Fine control of the atlantoaxial and atlantooccipital joints
What are the fascias of the neck?
Carotid sheath, pretracheal, and prevertebral
What is within the carotid sheath?
Common carotid artery, internal jugular vein, and VAGOSYMPATHETIC trunk
What is within the pretracheal fascia?
Muscles and viscera of the ventral neck
What is with in the prevertebral fascia?
All muscles associated with the vertebral column
What happens when the ventral vertebral muscles pass into the thorax?
Prevertebral fascia blend with the endothoracic fascia
What is the clinical significance of the region where the ventral vertebral muscles enter the thorax?
Possible route of infection
What are the two primary cutaneous muscles over the neck?
Cutaneous colli and Platysma
What is different about the cutaneous colli in horses?
Well developed near the manubrium, forms a thick cover over the caudal part of the jugular groove
What is the most ventral, non-cutaneous, muscle of the neck?
Sternocephalicus
What is the origin of the sternocephalicus?
Frist sternebra
What is the insertion of the sternocephalicus?
Mastoid and nuchal crest
What is the nerve that innervates the sternocephalicus?
Accessory nerve (CN XI)
What is the action of the sternocephalicus?
Unilateral lateral flexion of the neck and Bilateral ventral flexion of the neck
How is the sternocephalicus different in the horse?
Inserts on the manible and also thought to have a role in jaw opening
What are the two groups of muscles that control the position of the hyoid? (very basic)
Cranial and caudal group
What cranial muscles affect the positioning of the hyoid?
Muscles of the oral cavity, tongue, and pharynx
What is the caudal muscles that affect the positioning of the hyoid?
Sternohyoideus - Omohyoideus - Sternothyroideus - Thyrohyoideus
What once of the caudal muscles of the thyroid is not present in dogs and cats?
Omohyoideus
Where in the horse is omohyoideus located?
Lateral to the sternohyoideus
Where does the omohyoideus travel in horses?
Diverges from the sternohyoideus and goes more laterally toward the subscapular fascia
