Anatomy and functions of hyoid

ANATOMY/ FUNCTION OFANATOMY/ FUNCTION OF
THE HYOID APPARATUSTHE HYOID APPARATUS
Dr. Asma
House Surgeon,
ENT Department, Capital
Hospital

Anterior view Sagittal SectionPosterior view
Thyroid cart.
Thyroid cart.
Cricoid cart.
Arytenoid
cart.
Epiglottis
Hyoid
Arytenoid
cart.
Hyoid
Epiglottis
Cricoid cart.
Vocal Cord

 Helps to support the tongue
 Serves as an attachment point for several
muscles that help to elevate the larynx
during swallowing and speech.

 The hyoid bone
(Lingual Bone) is
unique in that it is
the only bone of the
body that does not
articulate with any
other bone.

 It is supported by the muscles
of the neck and in turn
supports the root of the
tongue.
 Its name is derived from the
Greek word hyoeides
meaning "shaped like the
letter upsilon" (υ). The hyoid
bone is shaped like a
horseshoe, and is suspended
from the tips of the styloid
processes of the temporal
bones by the stylohyoid
ligaments.

 Segments
 The body or basihyalThe body or basihyal
 The greater cornuaThe greater cornua
or thyrohyalsor thyrohyals
 The lesser cornua orThe lesser cornua or
ceratohyalsceratohyals

 The body or basihyal
 Its anterior surface is convex and directed forward and upward.Its anterior surface is convex and directed forward and upward.
 The anterior surface gives insertion to the to a number ofThe anterior surface gives insertion to the to a number of
musclesmuscles
 The posterior surface is smooth, concave, directed backwardThe posterior surface is smooth, concave, directed backward
and downward, and separated from the epiglottis by theand downward, and separated from the epiglottis by the
hyothyroid membranehyothyroid membrane
 In early life the lateral borders are connected to the greaterIn early life the lateral borders are connected to the greater
cornua by synchondroses; after middle life usually by bonycornua by synchondroses; after middle life usually by bony
union.union.

 The greater cornua or thyrohyals
 The greater cornua (cornua majora) project backward from the lateralThe greater cornua (cornua majora) project backward from the lateral
borders of the body; they are flattened from above downward; eachborders of the body; they are flattened from above downward; each
ends in a tubercle to which is fixed the lateral hyothyroid ligament.ends in a tubercle to which is fixed the lateral hyothyroid ligament.
 The lesser cornua or ceratohyals
 The lesser cornua (cornua minora) are two small, conical eminences,The lesser cornua (cornua minora) are two small, conical eminences,
attached by their bases to the angles of junction between the bodyattached by their bases to the angles of junction between the body
and greater cornua.and greater cornua.
 They are connected to the body of the bone by fibrous tissue, andThey are connected to the body of the bone by fibrous tissue, and
occasionally to the greater cornua by distinct diarthrodial jointsoccasionally to the greater cornua by distinct diarthrodial joints

Ossification
 The hyoid is ossified from six centers:
 two for the body, andtwo for the body, and
 one for each cornu.one for each cornu.
 Ossification commences in the
 greater cornua toward the end of fetal life,greater cornua toward the end of fetal life,
 in the body shortly afterward,in the body shortly afterward,
 and in the lesser cornua during the first or second year afterand in the lesser cornua during the first or second year after
birth.birth.

Triangles of NeckTriangles of Neck
Lumps In NeckLumps In Neck

Sternocleidomastoid
Trapezius
Anterior triangle
LUMPS IN NECKLUMPS IN NECK
Triangles of Neck
Divided into anterior and
posterior triangles by SCM.
Posterior Cervical Triangle

The Triangles are further divided into:
 Submandibular
Between digastric and mandibleBetween digastric and mandible
 Lymph nodesLymph nodes
 Submandibular or tail of parotidSubmandibular or tail of parotid
salivary glandssalivary glands
 CalculusCalculus
 InfectedInfected
 TumourTumour
 ObstructionObstruction
 Tense, painful swellingTense, painful swelling
 On eating, slowly resolves overOn eating, slowly resolves over
hourshours
 Returns on next eatingReturns on next eating
 Dental abcess (rare)Dental abcess (rare)
 Submental
Between hyoid and anterior belly of
digastric
 Lymph nodeLymph node
 Supra-hyoid thyroglossal cystSupra-hyoid thyroglossal cyst
 Dermoid cystDermoid cyst
 Dental abcess (rare)Dental abcess (rare)
Sternocleidomastoid
Trapezius

 Carotid
Anterior to SCM,
between SCM and
omohyoid
 Jugulo-digastricJugulo-digastric
lymph nodeslymph nodes
 Branchial cystBranchial cyst
 Carotid body tumourCarotid body tumour
(usually benign)(usually benign)
 VagusVagus
 SchwannomaSchwannoma
 NeuromaNeuroma
 ParagangliomaParaganglioma

 PubertyPuberty
 Multinodular goitreMultinodular goitre
(MNG)(MNG)
 Later thyroiditisLater thyroiditis
 Thyroglossal cystThyroglossal cyst
 Laryngeal tumourLaryngeal tumour
 Lymph nodes – pre- andLymph nodes – pre- and
para- trachealpara- tracheal
 Muscular
Between hyoid, SCM, and
omohyoid, anterior to omohyoid
 ThyroidThyroid
 NoduleNodule
 CystCyst
 CancerCancer
 PapillaryPapillary
 FollicularFollicular
 MedullaryMedullary
 LymphomaLymphoma
 Anaplastic carcinomaAnaplastic carcinoma
 AdenomaAdenoma
 Dominant nodule of MNGDominant nodule of MNG
 Diffuse enlargement (soft)Diffuse enlargement (soft)
 GravesGraves
 Early thyroiditisEarly thyroiditis
 PhysiologicalPhysiological
 PregnancyPregnancy

 Supraclavicular
Inferior to SCM and omohyoid
 ThyroidThyroid
 Cervical ribCervical rib
 Lymph nodesLymph nodes
Especially metsEspecially mets
 Gastric carcinomaGastric carcinoma
Troisier’s sign –
palpable Virchows node
 Lung cancerLung cancer
 Breast cancerBreast cancer
 Others – less commonOthers – less common

Anatomy and functions of hyoid

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